Wednesday, January 18, 2012

protein peptides| What is protein peptides|Papers on protein peptides|Research on protein peptides| Publications on protein peptides


1.
J Pept Sci. 2012 Jan 16. doi: 10.1002/psc.1439. [Epub ahead of print]

Antimicrobial activity of peptides derived from human ß-amyloid precursorprotein.

Source

Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Biomedical Center, Tornavägen 10, SE-221 84, Lund, Sweden.

Abstract

Antimicrobial peptides are important effector molecules of the innate immune system. Here, we describe that peptidesderived from the heparin-binding disulfide-constrained loop region of human ß-amyloid precursor protein are antimicrobial. The peptides investigated were linear and cyclic forms of NWCKRGRKQCKTHPH (NWC15) as well as the cyclic form comprising the C-terminal hydrophobic amino acid extension FVIPY (NWCKRGRKQCKTHPHFVIPY; NWC20c). Compared with the benchmark antimicrobial peptide LL-37, these peptides efficiently killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive Staphylococcus aureus and Bacillus subtilis, and the fungi Candida albicans and Candida parapsilosis. Correspondingly, fluorescence and electron microscopy demonstrated that the peptides caused defects in bacterial membranes. Analogously, the peptidespermeabilised negatively charged liposomes. Despite their bactericidal effect, the peptides displayed very limited hemolytic activities within the concentration range investigated and exerted very small membrane permeabilising effects on human epithelial cells. The efficiency of the peptides with respect to bacterial killing and liposome membrane leakage was in the order NWC20c > NWC15c > NWC15l, which also correlated to the adsorption density for these peptides at the model lipid membrane. Thus, whereas the cationic sequence is a minimum determinant for antimicrobial action, a constrained loop-structure as well as a hydrophobic extension further contributes to membrane permeabilising activity of this region of amyloid precursor protein. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

PMID:
22249992
[PubMed - as supplied by publisher]
2.
J Pept Sci. 2012 Jan 16. doi: 10.1002/psc.1430. [Epub ahead of print]

The use of 2,2'-dithiobis(5-nitropyridine) (DTNP) for deprotection and diselenide formation in protected selenocysteine-containing peptides.

Source

Department of Chemistry, Saint Michael's College, One Winooski Park, Colchester, VT, 05439, USA.

Abstract

In contrast to the large number of sidechain protecting groups available for cysteine derivatives in solid phase peptide synthesis, there is a striking paucity of analogous selenocysteine Se-protecting groups in the literature. However, the growing interest in selenocysteine-containing peptides and proteins requires a corresponding increase in availability of synthetic routes into these target molecules. It therefore becomes important to design new sidechain protection strategies for selenocysteine as well as multiple and novel deprotection chemistry for their removal. In this paper, we outline the synthesis of two new Fmoc selenocysteine derivatives [Fmoc-Sec(Meb) and Fmoc-Sec(Bzl)] to accompany the commercially available Fmoc-Sec(Mob) derivative and incorporate them into two model peptides. Sec-deprotection assays were carried out on these peptides using 2,2'-dithiobis(5-nitropyridine) (DTNP) conditions previously described by our group. The deprotective methodology was further evaluated as to its suitability towards mediating concurrent diselenide formation in oxytocin-templated target peptides. Sec(Mob) and Sec(Meb) were found to be extremely labile to the DTNP conditions whether in the presence or absence of thioanisole, whereas Sec(Bzl) was robust to DTNP in the absence of thioanisole but quite labile in its presence. In multiple Sec-containing model peptides, it was shown that bis-Sec(Mob)-containing systems spontaneously cyclize to the diselenide using 1 eq DTNP, whereas bis-Sec(Meb) and Sec(Bzl) models required additional manipulation to induce cyclization. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

PMID:
22249911
[PubMed - as supplied by publisher]
3.
Photosynth Res. 2012 Jan 17. [Epub ahead of print]

Comparison of Chloroflexus aurantiacus strain J-10-fl proteomes of cells grown chemoheterotrophically and photoheterotrophically.

Source

Biological Separations and Mass Spectrometry, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.

Abstract

Chloroflexus aurantiacus J-10-fl is a thermophilic green bacterium, a filamentous anoxygenic phototroph, and the model organism of the phylum Chloroflexi. We applied high-throughput, liquid chromatography-mass spectrometry in a global quantitative proteomics investigation of C. aurantiacus cells grown under oxic (chemoorganoheterotrophically) and anoxic (photoorganoheterotrophically) redox states. Our global analysis identified 13,524 high-confidence peptides that matched to 1,286 annotated proteins, 242 of which were either uniquely identified or significantly increased in abundance under photoheterotrophic culture condition. Fifty-four of the 242 proteins are previously characterized photosynthesis-related proteins, including chlorosome proteins, proteins involved in the bacteriochlorophyll biosynthesis, 3-hydroxypropionate (3-OHP) CO(2) fixation pathway, and components of electron transport chains. The remaining 188proteins have not previously been reported. Of these, five proteins were found to be encoded by genes from a novel operon and observed only in photoheterotrophically grown cells. These proteins candidates may prove useful in further deciphering the phototrophic physiology of C. aurantiacus and other filamentous anoxygenic phototrophs.

PMID:
22249883
[PubMed - as supplied by publisher]
4.
Food Funct. 2012 Jan 17. [Epub ahead of print]

Antihypertensive peptides from food proteins: a review.

Source

Institute of Food Science Research (CIAL, CSIC-UAM). Nicolás Cabrera, 9, Campus de la Universidad Autónoma de Madrid, 28049, Madrid, Spain. b.hernandez@csic.es.

Abstract

High blood pressure is considered as a significant health problem worldwide. In addition to numerous preventive and therapeutic drug treatments, important advances have been achieved in the identification of dietary compounds that may contribute to cardiovascular health. Among these compounds, peptides with antihypertensive properties received special attention in the past 15 years. Although milk proteins are still the main source of antihypertensive peptides, recently a remarkable increase has been noticed in the report of antihypertensive peptides released from other dietary sources. Most of these peptides have demonstrated their properties by in vitro assays. However, the evidence for their beneficial antihypertensive effects has to be based on animal experiments and clinical trials. This paper reviews the current data of the blood pressure-lowering activity of food-derived peptides demonstrated in vivo (animal models and humans). Other aspects, such as the mechanism of action and bioavailability of these peptides which play a key role in their antihypertensive effects are also summarized in this review.

PMID:
22249830
[PubMed - as supplied by publisher]
5.
Eur J Pharm Sci. 2012 Jan 10. [Epub ahead of print]

Preparation and characterization of insulin-loaded bioadhesive PLGA nanoparticles for oral administration.

Source

Department of Pharmaceutics, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China.

Abstract

Poly(d,l-lactide-co-glycolide) nanoparticles (PLGA-NP) have been extensively used as a drug delivery system forproteins and peptides. However, their negative surface charge decreases bioavailability under oral administration. Recently, cationically modified PLGA-NP has been introduced as novel carriers for oral delivery. The characteristics of the nanoparticles, such as particle size, surface charge, and bioadhesion are considered the most significant determinants of the effect of these nanoparticles both in vitro and in vivo. Our aim was to introduce and evaluate the physiochemical characteristics, bioadhesion, and biological activity of positively charged chitosan-coated PLGA-NP (CS-PLGA-NP), using insulin as a model drug. Results were compared to those of common negatively charged PLGA-NP and the in vitro cytotoxicity of the two types of nanoparticles was examined. These results indicate that both CS-PLGA-NP and PLGA-NP had a narrow size distribution, averaging less than 150nm. CS-PLGA-NP was positively charged (+43.1±0.3mV), exhibiting the cationic nature of chitosan, whereas PLGA-NP showed a negative surface charge (-1.72±0.2mV). CS-PLGA-NP exhibited stronger bioadhesive potency than PLGA-NP and much greater relative pharmacological availability with regard to orally delivered insulin. In addition, an evaluation of cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed no increase in toxicity in either kind of nanoparticle during the formulation process. The study proves that CS-PLGA-NP can be used as a vector in oral drug delivery systems for proteins and peptides due to its positive surface charge and bioadhesive properties.

Copyright © 2012. Published by Elsevier B.V.

PMID:
22248882
[PubMed - as supplied by publisher]
6.
Biochem Biophys Res Commun. 2012 Jan 10. [Epub ahead of print]

Superiority of PLK-2 as α-synuclein phosphorylating agent relies on unique specificity determinants.

Source

Department of Biological Chemistry and CNR Institute of Neurosciences, University of Padova, V.le G. Colombo 3, 35131 Padova, Italy.

Abstract

Phosphorylation of α-synuclein at Ser-129 is of crucial relevance to Parkinson's disease and related synucleinopathies. Here we provide biochemical evidence that PLK2 and to a lesser extent PLK3 are superior over CK2, as catalysts of Ser-129 phosphorylation both in full length α-synuclein and in a peptide reproducing the C-terminal segment of theprotein. By using substituted peptides we also show that the sequence surrounding Ser-129 is optimally shaped for undergoing phosphorylation by PLK2, with special reference to the two acidic residues at positions n-3 (Glu-126) and n+2 (Glu-131) whose replacement with alanine abrogates phosphorylation.

Copyright © 2012. Published by Elsevier Inc.

PMID:
22248692
[PubMed - as supplied by publisher]
7.
J Biotechnol. 2012 Jan 9. [Epub ahead of print]

Overexpression of a modified protein from amaranth seed in Escherichia coli and effect of environmental conditions on the protein expression.

Source

Centro de Investigación para el Desarrollo Integral Regional, CIDIIR-IPN, Sinaloa, Mexico.

Abstract

Amaranth seeds are considered as an excellent complementary source of food protein due to their balanced amino acid composition. Amarantin acidic subunit has the potential as a functional and nutraceutical protein, and it is structurally a good candidate for modification. The aim of this work was to improve its functionality, then the primary structure was modified into the third variable region of 11S globulins, by inserting antihypertensive peptides: four Val-Tyr in tandem and Arg-Ile-Pro-Pro in the C-terminal region. Modified protein was expressed in Escherichia coli Origami (DE3) and was purified. The culture conditions, including the culture media, temperature, agitation speed and air flow were tested in order to obtain an increased expression levels of the modified protein. A 2(3) factorial design was used for evaluate the effect of environmental conditions on modified protein production. The results indicated that the yield of modified proteincould be increased by up 3-fold in bioreactor as compared with flask. In addition, the temperature, the agitation speed and the oxygen were significant factors on the expression of the antihypertensive protein. The maximum production was 99mg protein-L(-1). The hydrolyzed protein showed a high inhibitory activity of the angiotensin converting enzyme (IC(50)=0.047mgmL(-1)).

Copyright © 2012 Elsevier B.V. All rights reserved.

PMID:
22248593
[PubMed - as supplied by publisher]
8.
Traffic. 2012 Jan 16. doi: 10.1111/j.1600-0854.2012.01329.x. [Epub ahead of print]

Structural basis of high-affinity nuclear localization signal interactions with importin-α

Source

School of Chemistry and Molecular Biosciences Australian Infectious Diseases Research Centre Australian Research Council Centre of Excellence for Integrative Legume Research, The University of Queensland, Brisbane, QLD 4072, Australia School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.

Abstract

Classical nuclear localization signals (cNLSs), comprising one (monopartite cNLSs) or two clusters of basic residues connected by a 10-12 residue linker (bipartite cNLSs), are recognised by the nuclear import factor importin-α. The cNLSs bind along a concave groove on importin-α, however, specificity determinants of cNLSs remain poorly understood. We present a structural and interaction analysis study of importin-α binding to both designed and naturally-occurring high-affinity cNLS-like sequences; the peptide inhibitors Bimax1 and Bimax2, and cNLS peptides of cap-binding protein 80. Our data suggest that cNLSs and cNLS-like sequences can achieve high affinity through maximising interactions at the importin-α minor site, and by taking advantage of multiple linker-region interactions. Our study defines an extended set of binding cavities on the importin-α surface, and also expands on recent observations that longer linker sequences are allowed, and that long-range electrostatic complementarity can contribute to cNLS-binding affinity. Altogether, our study explains the molecular and structural basis of the results of a number of recent studies including systematic mutagenesis and peptide library approaches, and provides an improved level of understanding on the specificity determinants of a cNLS. Our results have implications for identifying cNLSs in novel proteins.

© 2012 John Wiley & Sons A/S.

PMID:
22248489
[PubMed - as supplied by publisher]
9.
Retrovirology. 2012 Jan 16;9(1):6. [Epub ahead of print]

HIV infection and HERV expression: a review.

Abstract

ABSTRACT: The human genome contains multiple copies of retrovirus genomes known as endogenous retroviruses (ERVs) that have entered the germ-line at some point in evolution. Several of these proviruses have retained (partial) coding capacity, so that a number of viral proteins or even virus particles are expressed under various conditions. Human ERVs (HERVs) belong to the beta-, gamma-, or spuma- retrovirus groups. Endogenous delta- and lenti- viruses are notably absent in humans, although endogenous lentivirus genomes have been found in lower primates. Exogenous retroviruses that currently form a health threat to humans intriguingly belong to those absent groups. The best studied of the two infectious human retroviruses is the lentivirus human immunodeficiency virus (HIV) which has an overwhelming influence on its host by infecting cells of the immune system. One HIV-induced change is the induction of HERV transcription, often leading to induced HERV protein expression. This review will discuss the potential HIV-HERV interactions. Several studies have suggested that HERV proteins are unlikely to complement defective HIV virions, nor is HIV able to package HERV transcripts, probably due to low levels of sequence similarity. It is unclear whether the expression of HERVs has a negative, neutral, or positive influence on HIV-AIDS disease progression. A positive effect was recently reported by the specific expression of HERVs in chronically HIV-infected patients, which results in the presentation of HERV-derived peptides to CD8+ T-cells. These cytotoxic T-cells were not tolerant to HERV peptides, as would be expected for self-antigens, and consequently lysed the HIV-infected, HERV-presenting cells. This novel mechanism could control HIV replication and result in a low plasma viral load. The possibility of developing a vaccination strategy based on these HERV peptides will be discussed.

PMID:
22248111
[PubMed - as supplied by publisher]
10.
Clin Chem. 2012 Jan 12. [Epub ahead of print]

Candidate Serum Biomarkers for Prostate Adenocarcinoma Identified by mRNA Differences in Prostate Tissue and Verified with Protein Measurements in Tissue and Blood.

Source

Department of Health Sciences Research.

Abstract

BACKGROUND:

Improved tests are needed for detection and management of prostate cancer. We hypothesized that differential gene expression in prostate tissue could help identify candidate blood biomarkers for prostate cancer and that blood from men with advanced prostate disease could be used to verify the biomarkers presence in circulation.

METHODS:

We identified candidate markers using mRNA expression patterns from laser-capture microdissected prostate tissue and confirmed tissue expression using immunohistochemistry (IHC) for the subset of candidates having commercial antisera. We analyzed tissue extracts with tandem mass spectrometry (MS/MS) and measured blood concentrations using immunoassays and MS/MS of trypsin-digested, immunoextracted peptides.

RESULTS:

We selected 35 novel candidate prostate adenocarcinoma biomarkers. For all 13 markers having commercial antisera for IHC, tissue expression was confirmed; 6 showed statistical discrimination between nondiseased and malignant tissue, and only 5 were detected in tissue extracts by MS/MS. Sixteen of the 35 candidate markers were successfully assayed in blood. Four of 8 biomarkers measured by ELISA and 3 of 10 measured by targeted MS showed statistically significant increases in blood concentrations of advanced prostate cancer cases, compared with controls.

CONCLUSION:

Seven novel biomarkers identified by gene expression profiles in prostate tissue were shown to have statistically significant increased concentrations in blood from men with advanced prostate adenocarcinoma compared with controls: apolipoprotein C1 (APOC1), asporin (ASPN), cartilage oligomeric matrix protein (COMP), chemokine (C-X-C motif) ligand 11 (CXCL11), CXCL9, coagulation factor V (F5), and proprotein convertase subtilisin/kexin 6 (PCSK6).

PMID:
22247499
[PubMed - as supplied by publisher]
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11.
Arterioscler Thromb Vasc Biol. 2012 Jan 12. [Epub ahead of print]

CD36 Ectodomain Phosphorylation Blocks Thrombospondin-1 Binding: Structure-Function Relationships and Regulation by Protein Kinase C.

Source

Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland OH.

Abstract

OBJECTIVE:

CD36 phosphorylation on its extracellular domain inhibits binding of thrombospondin-1. The mechanisms of cellular CD36 ectodomain phosphorylation and whether it can be regulated in cells are not known. We determined structure-function relationships of CD36 phosphorylation related to thrombospondin-1 peptide binding in vitro and explored mechanisms regulating phosphorylation by protein kinase C (PKC) in melanoma cells.

METHODS AND RESULTS:

Phosphorylation of CD36 peptide on Thr92 by PKCα suppressed binding of thrombospondin-1 peptides in vitro, and the level of inhibition correlated with the level of phosphorylation. Basal phosphorylation levels of CD36 in vivo in platelets, endothelial cells, and melanoma cells were assessed by immunoprecipitation and immunoblot and were found to be very low. Treatment of CD36-transfected melanoma cells with phorbol 12-myristate 13-acetate (PMA), a PKC activator, induced substantial CD36 phosphorylation and decreased ligand-mediated recruitment of Src-family proteins to CD36. PMA treatment did not induce detectable extracellular or cell surface-associated kinase activity, and both cycloheximide and brefeldin A blocked CD36 phosphorylation.

CONCLUSIONS:

New protein synthesis and trafficking through the Golgi are required for PMA-induced CD36 phosphorylation, suggesting that phosphorylation probably occurs intracellularly. These studies suggest a novel in vivo pathway for CD36 phosphorylation that modulates cellular affinity for thrombospondin-related proteins to blunt vascular cell signaling.

PMID:
22247259
[PubMed - as supplied by publisher]
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12.
Proteomics. 2012 Jan 13. doi: 10.1002/pmic.201100517. [Epub ahead of print]

Electron Transfer Dissociation Mass Spectrometry in Proteomics.

Source

McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205.

Abstract

Mass spectrometry has rapidly evolved to become the platform of choice for proteomic analysis. While CID remains the major fragmentation method for peptide sequencing, electron transfer dissociation (ETD) is emerging as a complementary method for characterization of peptides and post-translational modifications (PTMs). Here, we review the evolution of ETD and some of its newer applications including characterization of PTMs, non-tryptic peptides and intactproteins. We will also discuss some of the unique features of ETD such as its complementarity with CID and the use of alternating CID/ETD along with issues pertaining to analysis of ETD data. The potential of ETD for applications such as multiple reaction monitoring and proteogenomics in the future will also be discussed.

Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PMID:
22246976
[PubMed - as supplied by publisher]
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13.
J Sci Food Agric. 2012 Jan 13. doi: 10.1002/jsfa.5573. [Epub ahead of print]

Hypocholesterolaemic and antioxidant activities of chickpea (Cicer arietinum L.) protein hydrolysates.

Source

Instituto de la Grasa-CSIC, Av. Padre García Tejero, 4, 41012-Seville, Spain. mdmar@cica.es.

Abstract

BACKGROUND:

Some dietary proteins possess biological properties which make them potential ingredients of functional or health-promoting foods. Many of these properties are attributed to bioactive peptides that can be released by controlled hydrolysis using exogenous proteases. The aim of this work was to test the improvement of hypocholesterolaemic and antioxidant activities of chickpea protein isolate by means of hydrolysis with alcalase and flavourzyme.

RESULTS:

All hydrolysates tested exhibited better hypocholesterolaemic activity when compared with chickpea proteinisolate. The highest cholesterol micellar solubility inhibition (50%) was found after 60 min of treatment with alcalase followed by 30 min of hydrolysis with flavourzyme. To test antioxidant activity of chickpea proteins three methods were used: β-carotene bleaching method, reducing power and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect since antioxidant activity of protein hydrolysates may not be attributed to a single mechanism. Chickpea hydrolysates showed better antioxidant activity in all assays, especially reducing power and DPPH scavenging effect than chickpeaprotein isolate.

CONCLUSION:

The results of this study showed the good potential of chickpea protein hydrolysates as bioactive ingredients. The highest bioactive properties could be obtained by selecting the type of proteases and the hydrolysis time. Copyright © 2012 Society of Chemical Industry.

Copyright © 2012 Society of Chemical Industry.

PMID:
22246802
[PubMed - as supplied by publisher]
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14.
Protein Cell. 2012 Jan 13. [Epub ahead of print]

Study on the chaperone properties of conserved GTPases.

Source

RNA Lab, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.

Abstract

As a large family of hydrolases, GTPases are widespread in cells and play the very important biological function of hydrolyzing GTP into GDP and inorganic phosphate through binding with it. GTPases are involved in cell cycle regulation, protein synthesis, and protein transportation. Chaperones can facilitate the folding or refolding of nascentpeptides and denatured proteins to their native states. However, chaperones do not occur in the native structures in which they can perform their normal biological functions. In the current study, the chaperone activity of the conserved GTPases of Escherichia coli is tested by the chemical denaturation and chaperone-assisted renaturation of citrate synthase and α-glucosidase. The effects of ribosomes and nucleotides on the chaperone activity are also examined. Our data indicate that these conserved GTPases have chaperone properties, and may be ancestral protein folding factors that have appeared before dedicated chaperones.

PMID:
22246579
[PubMed - as supplied by publisher]
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15.
J Mol Model. 2012 Jan 14. [Epub ahead of print]

Full-length structural model of RET3 and SEC21 in COPI: identification of binding sites on the appendage for accessory protein recruitment motifs.

Source

Department of Anatomy and Cell Biology, McGill University, Strathcona Building, 3640 University Street, Montreal, QC H3A 2B2, Canada.

Abstract

COPI, a 600 kD heptameric complex (consisting of subunits α, β, γ, δ, ε, ζ, and β') "coatomer," assembles non-clathrin-coated vesicles and is responsible for intra-Golgi and Golgi-to-ER protein trafficking. Here, we report the three-dimensional structures of the entire sequences of yeast Sec21 (γ-COPI mammalian ortholog), yeast Ret3 (ζ-COPI mammalian ortholog), and the results of successive molecular dynamics investigations of the subunits and assembly based on a protein-protein docking experiment. The three-dimensional structures of the subunits in their complexes indicate the residues of the two subunits that impact on assembly, the conformations of Ret3 and Sec21, and their binding orientations in the complexed state. The structure of the appendage domain of Sec21, with its two subdomains-the platform and the β-sandwich, was investigated to explore its capacity to bind to accessory protein recruitment motifs. Our study shows that a binding site on the platform is capable of binding the Eps15 DPF and epsin DPW2peptides, whereas the second site on the platform and the site on the β-sandwich subdomain were found to selectively bind to the amphiphysin FXDXF and epsin DPW1 peptides, respectively. Identifying the regions of both the platform and sandwich subdomains involved in binding each peptide motif clarifies the mechanism through which the appendage domain of Sec21 engages with the accessory proteins during the trafficking process of non-clathrin-coated vesicles.

PMID:
22246286
[PubMed - as supplied by publisher]
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16.
Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan 8. [Epub ahead of print]

A novel molluscan sigma-like glutathione S-transferase from Manila clam, Ruditapes philippinarum: Cloning, characterization and transcriptional profiling.

Source

Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province, 690-756, Republic of Korea.

Abstract

Glutathione S-transferases (GSTs) are versatile enzymes, act as primary intracellular detoxifiers and contribute to a broad range of physiological processes including cellular defense. In this study, a full-length cDNA representing a novel sigma-like GST was identified from Manila clam, Ruditapes philippinarum (RpGSTσ). RpGSTσ (884bp) was found to possess an open reading frame of 609bp. The encoded polypeptide (203 amino acids) had a predicted molecular mass of 23.21kDa and an isoelectric point of 7.64. Sequence analysis revealed two conserved GST domain profiles in N- and C-termini. Alignment studies revealed that the identity between deduced peptides of RpGSTσ and known GSTσ members was relatively low (<35%), except a previously identified Manila clam GSTσ isoform (87.2%). Phylogenetic analysis indicated that RpGSTσ clustered together with molluscan GSTσ homologs, which were closely related to insect GSTσs. The RpGSTσ was subsequently cloned and expressed as recombinant protein, in order to characterize its biological activity. The recombinant RpGSTσ exhibited characteristic glutathione conjugating catalytic activity toward 1-chloro-2,4-dinitrobenzene, 3,4-dichloronitrobenzene and ethacrynic acid. It had an optimal pH and temperature of 8.0 and 35°C, respectively. Expression profiles under normal conditions and in response to lipopolysaccharide-, poly I:C- and Vibrio tapetis-challenges were also investigated. RpGSTσ demonstrated a differential tissue distribution with robust transcription in gills of normal animals. We explored potential association of GSTσ in cellular defense during bacterial infection and found that in challenged clams, RpGSTσ gene was significantly induced in internal and external tissues, in conjunction with manganese- as well as copper-zinc superoxide dismutase (MnSOD and CuZnSOD) genes. Moreover, the induction was remarkably higher in hemocytes than in gill. Collectively, our findings suggested that RpGSTσ could play a significant role in cellular defense against oxidative stress caused by bacteria, in conjunction with other antioxidant enzymes, such as SODs.

Copyright © 2012. Published by Elsevier Inc.

PMID:
22245757
[PubMed - as supplied by publisher]
17.
Neuropeptides. 2012 Jan 13. [Epub ahead of print]

Activation of CRHR2 exerts an inhibitory effect on the expression of collapsin response mediator protein 3 in hippocampal neurons.

Source

Department of Physiology and The Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai 200433, PR China.

Abstract

Corticotropin-releasing hormone (CRH) family peptides as well as their receptors have been shown to exhibit various functions in hippocampus. However, effects of CRH receptors activation on collapsin response mediator protein 3 (CRMP3), the key protein for dendrite outgrowth and cell apoptosis, remain unclear. In the present study, we determined the effects of CRHR1 and CRHR2 on CRMP3 expression in cultured hippocampal neurons. CRH and urocortin II (UCNII) dose-dependently suppressed CRMP3 mRNA and protein expression. The inhibitory effect on CRMP3 expression was completely reversed by CRHR2 antagonist but not by CRHR1 antagonist. Investigations on the signaling pathways of UCNII showed that CRHR2 mediated UCNII-induced increase in phosphorylated phospholipase C (PLC)-β3 expression. Blocking PLC activity with U73122 and PKC with Gö6976 completely prevented UCNII-inhibited CRMP3 expression. Our results suggest that CRHR2 activation decrease CRMP3 expression in hippocampal neurons via a mechanism that is dependent on PLC/PKC signaling pathways.

Copyright © 2011 Elsevier Ltd. All rights reserved.

PMID:
22245585
[PubMed - as supplied by publisher]
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18.
Adv Drug Deliv Rev. 2012 Jan 4. [Epub ahead of print]

Oral biodrug delivery using cell-penetrating peptide.

Source

Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Suez Canal University, Ismailia 415-22, Egypt.

Abstract

During the past few decades, the novel biotherapeutic agents such as peptides and proteins have been contributed to the treatment of several diseases. However, their oral absorption is significantly limited due to their poor delivery through the intestinal mucosa. Therefore, the feasible approaches are needed for improving the oral bioavailability of biodrugs. Recently, cell-penetrating peptides (CPPs) such as HIV-1 Tat, penetratin and oligoarginine are considered as a useful tool for the intracellular delivery of therapeutic macromolecules. Hence, it was expected that the ability of CPPs may be applicable to enhance the absorption of biodrugs through intestinal epithelial membrane. CPPs are likely to become powerful tools for overcoming the low permeability of therapeutic peptides and proteins through the intestinal membrane, the major barrier to their oral delivery. Further advantage of this promising strategy is that this successful intestinal absorption could be achieved by more convenient methodology, coadministration of CPP with drugs via intermolecular interaction among them. Hereafter, the further establishment of delivery system based on CPPs is required to realize the development of the oral forms of therapeutic peptides and proteins. The aim here is to introduce our vision focusing on oral biodrug delivery by the use of CPPs as potential peptide carrier in order to provide new information in the design and development of new oral delivery systems for novel biotherapeutics.

Copyright © 2011. Published by Elsevier B.V.

PMID:
22245080
[PubMed - as supplied by publisher]
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19.
Neuropharmacology. 2012 Jan 2. [Epub ahead of print]

Substance P activates ADAM9 mRNA expression and induces α-secretase-mediated amyloid precursor protein cleavage.

Source

Institute of Cell Biology and Neurobiology, CNR, Via del Fosso di Fiorano, 65, 00143 Rome, Italy.

Abstract

Altered levels of Substance P (SP), a neuropeptide endowed with neuroprotective and anti-apoptotic properties, were found in brain areas and spinal fluid of Alzheimer's disease (AD) patients. One of the hallmarks of AD is the abnormal extracellular deposition of neurotoxic beta amyloid (Aβ) peptides, derived from the proteolytic processing of amyloid precursor protein (APP). In the present study, we confirmed, the neurotrophic action of SP in cultured rat cerebellar granule cells (CGCs) and investigated its effects on APP metabolism. Incubation with low (5 mM) potassium induced apoptotic cell death of CGCs and amyloidogenic processing of APP, whereas treatment with SP (200 nM) reverted these effects via NK1 receptors. The non-amyloidogenic effect of SP consisted of reduction of Aβ(1-42), increase of sAPPα and enhanced α-secretase activity, without a significant change in steady-state levels of cellular APP. The intracellular mechanisms whereby SP alters APP metabolism were further investigated by measuring mRNA and/or steady-state protein levels of key enzymes involved with α-, β- and γ-secretase activity. Among them, Adam9, both at the mRNA and protein level, was the only enzyme to be significantly down-regulated following the induction of apoptosis (K5) and up-regulated after SP treatment. In addition to its neuroprotective properties, this study shows that SP is able to stimulate non-amyloidogenic APP processing, thereby reducing the possibility of generation of toxic Aβ peptides in brain.

Copyright © 2011 Elsevier Ltd. All rights reserved.

PMID:
22244942
[PubMed - as supplied by publisher]
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20.
Biochim Biophys Acta. 2011 Dec 30. [Epub ahead of print]

Identification and classification of conopeptides using profile Hidden Markov Models.

Source

Estonian Biocentre, Riia 23, 51010, Tartu, Estonia.

Abstract

Conopeptides are small toxins produced by predatory marine snails of the genus Conus. They are studied with increasing intensity due to their potential in neurosciences and pharmacology. The number of existing conopeptides is estimated to be 1 million, but only about 1000 have been described to date. Thanks to new high-throughput sequencing technologies the number of known conopeptides is likely to increase exponentially in the near future. There is therefore a need for a fast and accurate computational method for identification and classification of the novel conopeptides in large data sets. 62 profile Hidden Markov Models (pHMMs) were built for prediction and classification of all described conopeptide superfamilies and families, based on the different parts of the corresponding protein sequences. These models showed very high specificity in detection of new peptides. 56 out of 62 models do not give a single false positive in a test with the entire UniProtKB/Swiss-Prot protein sequence database. Our study demonstrates the usefulness of mature peptide models for automatic classification with accuracy of 96% for the mature peptide models and 100% for the pro- and signal peptide models. Our conopeptide profile HMMs can be used for finding and annotation of new conopeptides from large datasets generated by transcriptome or genome sequencing. To our knowledge this is the first time this kind of computational method has been applied to predict all known conopeptide superfamilies and some conopeptide families.

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