| 18282640 |
A novel antimicrobial peptide from amphibian skin secretions of Odorrana grahami |
10.1016/j.peptides.2008.01.004. |
Peptides |
A novel antimicrobial peptide from amphibian skin secretions of Odorrana grahami
Abstract
- A novel antimicrobial peptide named odorranain-NR was identified from skin secretions of the diskless odorous frog, Odorrana grahami. It is composed of 23 amino acids with an amino acid sequence of GLLSGILGAGKHIVCGLTGCAKA. Odorranain-NR was classified into a novel family of antimicrobial peptide although it shared similarity with amphibian antimicrobial peptide family of nigrocin. Odorranain-NR has an unusual intramolecular disulfide-bridged hexapeptide segment that is different from the intramolecular disulfide-bridged heptapeptide segment at the C-terminal end of nigrocins. Furthermore, the -AKA fragment at the C-terminal of odorranain-NR is also different from nigrocins. Three different cDNAs encoding two odorranain-NR precursors and only one mature odorranain-NR was cloned from the cDNA library of the skin of O. grahami. This peptide showed antimicrobial activities against tested microorganisms except Escherichia coli (ATCC25922). Its antimicrobial mechanisms were investigated by transmission electron microcopy. Odorranain-NR exerted its antimicrobial functions by various means depending on different microorganisms.
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| 18291642 |
Structure-based design of novel groups for use in the P1 position of thrombin inhibitor scaffolds. Part 2: N-acetamidoimidazoles |
10.1016/j.bmcl.2008.01.098. |
Bioorg Med Chem Lett |
Structure-based design of novel groups for use in the P1 position of thrombin inhibitor scaffolds. Part 2: N-acetamidoimidazoles
Abstract
- Guided by X-ray crystallography of thrombin-inhibitor complexes and molecular modeling, alkylation of the N1 nitrogen of the imidazole P1 ligand of the pyridinoneacetamide thrombin inhibitor 1 with various acetamide moieties furnished inhibitors with significantly improved thrombin potency, trypsin selectivity, functional in vitro anticoagulant potency and in vivo antithrombotic efficacy. In the pyrazinoneacetamide series, oral bioavailability was also improved.
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| 18295795 |
Alpha-RgIA, a novel conotoxin that blocks the alpha9alpha10 nAChR: structure and identification of key receptor-binding residues |
10.1016/j.jmb.2008.01.082. |
J Mol Biol |
Alpha-RgIA, a novel conotoxin that blocks the alpha9alpha10 nAChR: structure and identification of key receptor-binding residues
Abstract
- Alpha-conotoxins are small disulfide-constrained peptides from cone snails that act as antagonists at specific subtypes of nicotinic acetylcholine receptors (nAChRs). The 13-residue peptide alpha-conotoxin RgIA (alpha-RgIA) is a member of the alpha-4,3 family of alpha-conotoxins and selectively blocks the alpha9alpha10 nAChR subtype, in contrast to another well-characterized member of this family, alpha-conotoxin ImI (alpha-ImI), which is a potent inhibitor of the alpha7 and alpha3beta2 nAChR subtypes. In this study, we have altered side chains in both the four-residue and the three-residue loops of alpha-RgIA, and have modified its C-terminus. The effects of these changes on activity against alpha9alpha10 and alpha7 nAChRs were measured; the solution structures of alpha-RgIA and its Y10W, D5E, and P6V analogues were determined from NMR data; and resonance assignments were made for alpha-RgIA [R9A]. The structures for alpha-RgIA and its three analogues were well defined, except at the chain termini. Comparison of these structures with reported structures of alpha-ImI reveals a common two-loop backbone architecture within the alpha-4,3 family, but with variations in side-chain solvent accessibility and orientation. Asp5, Pro6, and Arg7 in loop 1 are critical for blockade of both the alpha9alpha10 and the alpha7 subtypes. In loop 2, alpha-RgIA [Y10W] had activity near that of wild-type alpha-RgIA, with high potency for alpha9alpha10 and low potency for alpha7, and had a structure similar to that of wild type. By contrast, Arg9 in loop 2 is critical for specific binding to the alpha9alpha10 subtype, probably because it is larger and more solvent accessible than Ala9 in alpha-ImI. Our findings contribute to a better understanding of the molecular basis for antagonism of the alpha9alpha10 nAChR subtype, which is a target for the development of analgesics for the treatment of chronic neuropathic pain.
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| 18296648 |
Distinct functions of natural ADAM-15 cytoplasmic domain variants in human mammary carcinoma |
10.1158/1541-7786.MCR-07-2028. |
Mol Cancer Res |
Distinct functions of natural ADAM-15 cytoplasmic domain variants in human mammary carcinoma
Abstract
- Adamalysins [a disintegrin and metalloproteinase (ADAM)] are a family of cell surface transmembrane proteins that have broad biological functions encompassing proteolysis, adhesion, and cell signal regulation. We previously showed that the cytoplasmic domain of ADAM-15 interacts with Src family protein tyrosine kinases and the adaptor protein growth factor receptor binding protein 2 (Grb2). In the present study, we have cloned and characterized four alternatively spliced forms of ADAM-15, which differ only in their cytoplasmic domains. We show that the four ADAM-15 variants were differentially expressed in human mammary carcinoma tissues compared with normal breast. The expression of the individual isoforms did not correlate with age, menopausal status, tumor size or grade, nodal status, Nottingham Prognostic Index, or steroid hormone receptor status. However, higher levels of two isoforms (ADAM-15A and ADAM-5B) were associated with poorer relapse-free survival in node-negative patients, whereas elevated ADAM-15C correlated with better relapse-free survival in node-positive, but not in node-negative, patients. The expression of ADAM-15A and ADAM-15B variants in MDA-MB-435 cells had differential effects on cell morphology, with adhesion, migration, and invasion enhanced by expression of ADAM-15A, whereas ADAM-15B led to reduced adhesion. Using glutathione S-transferase pull-down assays, we showed that the cytoplasmic domains of ADAM-15A, ADAM-15B, and ADAM-15C show equivalent abilities to interact with extracellular signal-regulated kinase and the adaptor molecules Grb2 and Tks5/Fish, but associate in an isoform-specific fashion with Nck and the Src and Brk tyrosine kinases. These data indicate that selective expression of ADAM-15 variants in breast cancers could play an important role in determining tumor aggressiveness by interplay with intracellular signaling pathways.
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| 18303848 |
Antimycobacterial serratamolides and diacyl peptoglucosamine derivatives from Serratia sp |
10.1021/np7007126. |
J Nat Prod |
Antimycobacterial serratamolides and diacyl peptoglucosamine derivatives from Serratia sp
Abstract
- The cyclodepsipeptide serratamolide A ( 1) and five closely related compounds together with three new glucosamine derivatives were isolated by bioactivity-guided chromatography from the XAD adsorber resin extract of a Serratia sp. The structures of the compounds were elucidated by 2D NMR and MS analyses. In addition to the known serratamolide A ( 1) with two C 10 alkyl chains, its derivatives always contained one C 10 chain combined with either C 12:1, C 12, C 11, C 9, or C 8 chains. The glucosamine derivatives contained a common core consisting of an N-butyl-alpha-glucopyranosylamide, which was acylated at the C-1 oxygen with valine. The differences between the derivatives arise from the nature of the acyl groups attached to the N-terminus of valine, which were identified as the linear fatty acid moieties C 16:1, C 15, or C 14. Each compound was present in two isomeric forms arising from racemization of the valine moiety. All compounds showed antibiotic activity against Mycobacterium diernhoferi and other rapidly growing mycobacteria.
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| 18305354 |
Unnarmicins A and C, new antibacterial depsipeptides produced by marine bacterium Photobacterium sp. MBIC06485 |
10.1038/ja.2008.103. |
J Antibiot (Tokyo) |
Unnarmicins A and C, new antibacterial depsipeptides produced by marine bacterium Photobacterium sp. MBIC06485
Abstract
- Two new antibiotic depsipeptides, unnarmicins C (1) and A (2), were isolated from the fermentation broth of a marine bacterium, Photobacterium sp. strain MBIC06485. The structure of 1 was established by spectroscopic studies and chiral analyses of its chemical degradation/conversion products, and that of 2 by comparing its NMR, MS, and CD data with those of 1. Both compounds selectively inhibited the growth of two strains belonging to the genus Pseudovibrio, one of the most prevalent genera in the marine environments within the class Alphaproteobacteria.
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| 18305355 |
Pedein A and B: production, isolation, structure elucidation and biological properties of new antifungal cyclopeptides from Chondromyces pediculatus (Myxobacteria) |
10.1038/ja.2008.104. |
J Antibiot (Tokyo) |
Pedein A and B: production, isolation, structure elucidation and biological properties of new antifungal cyclopeptides from Chondromyces pediculatus (Myxobacteria)
Abstract
- Two new secondary metabolites, named pedein A and B, were isolated from the cell mass of the myxobacterium Chondromyces pediculatus. Their planar structures were elucidated by spectroscopic methods, in particular 2D NMR as 24-membered cyclic hexapeptides composed of a variable tryptophan residue, glycine, sarcosine and three unusual hydroxy beta- and gamma-amino acids. The main component, pedein A, strongly inhibited the growth of yeasts and fungi, induced hemolysis of erythrocytes, and caused changes in membrane permeability of Rhodotorula glutinis. The structures of the pedeins are closely related to the large family of the microsclerodermins, which have been isolated from lithistid sponges of Microscleroderma and Theonella species.
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| 18307186 |
Synthesis, characterisation, and in vitro evaluation of Pro2-Ile3-S-deoxo-amaninamide and Pro2-D-allo-Ile3-S-deoxo-amaninamide: implications for structure-activity relationships in amanitin conformation and toxicity |
10.1002/chem.200701297. |
Chemistry |
Synthesis, characterisation, and in vitro evaluation of Pro2-Ile3-S-deoxo-amaninamide and Pro2-D-allo-Ile3-S-deoxo-amaninamide: implications for structure-activity relationships in amanitin conformation and toxicity
Abstract
- The amatoxins are a family of toxic bicyclic peptides that inhibit RNA polymerase II. Herein we discuss an improved synthesis of these compounds from easily obtainable amino acids by means of a solid-phase methodology. Interestingly, we obtained two products of the same mass following our final macrocyclisation, relating to a similar distribution of products described in some previous reports. One of these products was the desired amatoxin; Pro(2)-Ile(3)-S-deoxo-amaninamide 1 b. The other compound, after thorough investigation, was confirmed to be the epimer Pro(2)-D-allo-Ile(3)-S-deoxo-amaninamide 1 a, not an atropisomer structure as previously suggested in syntheses of related amanitin analogues. Crystallographic data of 1 a confirms the presence of a betaII-turn, rather than a betaI-turn common to the natural toxin and 1 b. This difference explains the large variation in CD spectra, although it seems to have relatively little effect on the bioactivity in vitro. These data provide new insights into the bicyclic amatoxin structure.
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| 18318008 |
Large-scale phosphoproteome analysis of human liver tissue by enrichment and fractionation of phosphopeptides with strong anion exchange chromatography |
10.1002/pmic.200700884. |
Proteomics |
Large-scale phosphoproteome analysis of human liver tissue by enrichment and fractionation of phosphopeptides with strong anion exchange chromatography
Abstract
- The mixture of phosphopeptides enriched from proteome samples are very complex. To reduce the complexity it is necessary to fractionate the phosphopeptides. However, conventional enrichment methods typically only enrich phosphopeptides but not fractionate phosphopeptides. In this study, the application of strong anion exchange (SAX) chromatography for enrichment and fractionation of phosphopeptides was presented. It was found that phosphopeptides were highly enriched by SAX and majority of unmodified peptides did not bind onto SAX. Compared with Fe(3+) immobilized metal affinity chromatography (Fe(3+)-IMAC), almost double phosphopeptides were identified from the same sample when only one fraction was generated by SAX. SAX and Fe(3+)-IMAC showed the complementarity in enrichment and identification of phosphopeptides. It was also demonstrated that SAX have the ability to fractionate phosphopeptides under gradient elution based on their different interaction with SAX adsorbent. SAX was further applied to enrich and fractionate phosphopeptides in tryptic digest of proteins extracted from human liver tissue adjacent to tumorous region for phosphoproteome profiling. This resulted in the highly confident identification of 274 phosphorylation sites from 305 unique phosphopeptides corresponding to 168 proteins at false discovery rate (FDR) of 0.96%.
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| 18323244 |
Synthesis of a phenylalanine-rich peptide as potential anthelmintic and cytotoxic agent |
None |
Acta Pol Pharm |
Synthesis of a phenylalanine-rich peptide as potential anthelmintic and cytotoxic agent
Abstract
- A natural cyclic heptapeptide segetalin D [VIII] was synthesized by coupling of tripeptide unit Boc-Pro-Gly-Leu-OMe [V] with tetrapeptide unit Boc-Ser-Phe-Ala-Phe-OMe [VI] after proper deprotection at carboxyl and amino ends followed by cyclization of linear peptide segment. Structure of VIII was confirmed by spectral and elemental analyses. The newly synthesized cyclopeptide was tested for its antibacterial, antifungal, anthelmintic and cytotoxic activities. Compound VIII showed high cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines with CTC50 values of 7.54 and 13.56 microM. Moreover, VIII exhibited potent anthelmintic activity against earthworms Eudrilus species, Megascoplex konkanensis and Pontoscotex corethruses at a dose of 2 mg/mL.
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| 18327911 |
Antineoplastic agents. 536. New sources of naturally occurring cancer cell growth inhibitors from marine organisms, terrestrial plants, and microorganisms(1a,) |
10.1021/np700738k. |
J Nat Prod |
Antineoplastic agents. 536. New sources of naturally occurring cancer cell growth inhibitors from marine organisms, terrestrial plants, and microorganisms(1a,)
Abstract
- Bioassay-guided fractionation of extracts of various plants, marine organisms, and microorganisms has led to the discovery of new natural sources of a number of known compounds that have significant biological activity. The isolation of interesting and valuable cancer cell growth inhibitors including majusculamide C ( 1), axinastatin 5 ( 5), bengazoles A ( 6), B ( 7), and E ( 8), manzamine A ( 10), jaspamide ( 11), and neoechinulin A ( 19) has been summarized.
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| 18330887 |
The geodiamolide H, derived from Brazilian sponge Geodia corticostylifera, regulates actin cytoskeleton, migration and invasion of breast cancer cells cultured in three-dimensional environment |
10.1002/jcp.21432. |
J Cell Physiol |
The geodiamolide H, derived from Brazilian sponge Geodia corticostylifera, regulates actin cytoskeleton, migration and invasion of breast cancer cells cultured in three-dimensional environment
Abstract
- We are investigating effects of the depsipeptide geodiamolide H, isolated from the Brazilian sponge Geodia corticostylifera, on cancer cell lines grown in 3D environment. As shown previously geodiamolide H disrupts actin cytoskeleton in both sea urchin eggs and breast cancer cell monolayers. We used a normal mammary epithelial cell line MCF 10A that in 3D assay results formation of polarized spheroids. We also used cell lines derived from breast tumors with different degrees of differentiation: MCF7 positive for estrogen receptor and the Hs578T, negative for hormone receptors. Cells were placed on top of Matrigel. Spheroids obtained from these cultures were treated with geodiamolide H. Control and treated samples were analyzed by light and confocal microscopy. Geodiamolide H dramatically affected the poorly differentiated and aggressive Hs578T cell line. The peptide reverted Hs578T malignant phenotype to polarized spheroid-like structures. MCF7 cells treated by geodiamolide H exhibited polarization compared to controls. Geodiamolide H induced striking phenotypic modifications in Hs578T cell line and disruption of actin cytoskeleton. We investigated effects of geodiamolide H on migration and invasion of Hs578T cells. Time-lapse microscopy showed that the peptide inhibited migration of these cells in a dose-dependent manner. Furthermore invasion assays revealed that geodiamolide H induced a 30% decrease on invasive behavior of Hs578T cells. Our results suggest that geodiamolide H inhibits migration and invasion of Hs578T cells probably through modifications in actin cytoskeleton. The fact that normal cell lines were not affected by treatment with geodiamolide H stimulates new studies towards therapeutic use for this peptide.
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| 18355315 |
Purification and structural characterization of a D-amino acid-containing conopeptide, conomarphin, from Conus marmoreus |
10.1111/j.1742-4658.2008.06352.x. |
FEBS J |
Purification and structural characterization of a D-amino acid-containing conopeptide, conomarphin, from Conus marmoreus
Abstract
- Cone snails, a group of gastropod animals that inhabit tropical seas, are capable of producing a mixture of peptide neurotoxins, namely conotoxins, for defense and predation. Conotoxins are mainly disulfide-rich short peptides that act on different ion channels, neurotransmitter receptors, or transporters in the nervous system. They exhibit highly diverse compositions, structures, and biological functions. In this work, a novel Cys-free 15-residue conopeptide from Conus marmoreus was purified and designated as conomarphin. Conomarphin is unique because of its D-configuration Phe at the third residue from the C-terminus, which was identified using HPLC by comparing native conomarphin fragments and the corresponding synthetic peptides cleaved by different proteases. Surprisingly, the cDNA-encoded precursor of conomarphin was found to share the conserved signal peptide with other M-superfamily conotoxins, clearly indicating that conomarphin should belong to the M-superfamily, although conomarphin shares no homology with other six-Cys-containing M-superfamily conotoxins. Furthermore, NMR spectroscopy experiments established that conomarphin adopts a well-defined structure in solution, with a tight loop in the middle of the peptide and a short 3(10)-helix at the C-terminus. By contrast, no loop in L-Phe13-conomarphin was found, which suggests that D-Phe13 is essential for the structure of conomarphin. In conclusion, conomarphin may represent a new conotoxin family, whose biological activity remains to be identified.
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| 18362344 |
Molecular basis of thrombin recognition by protein C inhibitor revealed by the 1.6-A structure of the heparin-bridged complex |
10.1073/pnas.0711055105. |
Proc Natl Acad Sci U S A |
Molecular basis of thrombin recognition by protein C inhibitor revealed by the 1.6-A structure of the heparin-bridged complex
Abstract
- Protein C inhibitor (PCI) is a serpin with many roles in biology, including a dual role as pro- and anticoagulant in blood. The protease specificity and local function of PCI depend on its interaction with cofactors such as heparin-like glycosaminoglycans (GAGs) and thrombomodulin (TM). Both cofactors significantly increase the rate of thrombin inhibition, but GAGs serve to promote the anticoagulant activity of PCI, and TM promotes its procoagulant function. To gain insight into how PCI recognition of thrombin is aided by these cofactors, we determined a crystallographic structure of the Michaelis complex of PCI, thrombin, and heparin to 1.6 A resolution. Thrombin interacts with PCI in an unusual fashion that depends on the length of PCI's reactive center loop (RCL) to align the heparin-binding sites of the two proteins. The principal exosite contact is engendered by movement of thrombin's 60-loop in response to the unique P2 Phe of PCI. This mechanism of communication between the active site of thrombin and its recognition exosite is previously uncharacterized and may relate to other thrombin substrate-cofactor interactions. The cofactor activity of heparin thus depends on the formation of a heparin-bridged Michaelis complex and substrate-induced exosite contacts. We also investigated the cofactor effect of TM, establishing that TM bridges PCI to thrombin through additional direct interactions. A model of the PCI-thrombin-TM complex was built and evaluated by mutagenesis and suggests distinct binding sites for heparin and TM on PCI. These data significantly improve our understanding of the cofactor-dependent roles of PCI in hemostasis.
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| 18367182 |
Clinical efficacy of highly purified urinary FSH versus recombinant FSH in volunteers undergoing controlled ovarian stimulation for in vitro fertilization: a randomized, multicenter, investigator-blind trial |
10.1016/j.fertnstert.2008.01.064. |
Fertil Steril |
Clinical efficacy of highly purified urinary FSH versus recombinant FSH in volunteers undergoing controlled ovarian stimulation for in vitro fertilization: a randomized, multicenter, investigator-blind trial
Abstract
- To compare the efficacy of highly purified human urinary follicle stimulating hormone (HP-hFSH) versus human recombinant follitropin-alpha (rFSH) in volunteers undergoing controlled ovarian stimulation for IVF.
A randomized, controlled, investigator-blind trial.
Four assisted reproductive technology centers.
One hundred fifty-two IVF patients.
Volunteers, aged 18-39, were randomized to HP-hFSH (n = 76) versus rFSH (n = 76) at a starting dose of 300 IU in down-regulated cycles.
Number of oocytes, clinical pregnancy rate, and live birth rate with HP-hFSH versus rFSH.
The total IU of gonadotropin used did not differ between the two groups. There was no difference in number of oocytes retrieved with HP-hFSH (mean = 16.3) compared with rFSH (mean = 17.1), confidence interval (CI) of difference = -3.79 to +2.18. Clinical pregnancy rate, as defined by the presence of a gestational sac, was 48.7% (CI = 37.0%-60.4%) with HP-hFSH versus 44.7% (CI = 33.3%-56.6%) with rFSH (CI of difference = -11.9% to +19.8%). Live birth rate was 38.2% (29 of 76) in both groups (CI = 27.2%-50.0%), for a difference between groups of 0.0% (CI of the difference = -15.4% to +15.4%).
There were no statistically significant differences in mean oocyte number, clinical pregnancy rate, or live birth rate between HP-hFSH versus rFSH.
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