摘要:

TheO‐acyl isopeptide method was developed for the efficient preparation of difficult sequence‐containing peptide. Furthermore, development of theO‐acyl isodipeptide unit for Fmoc chemistry simplified its synthetic procedure by solid‐phase peptide synthesis. Here, we report a novel isodipeptide unit for Boc chemistry, and the unit was successfully applied to the synthesis of amyloidβpeptide. Combination of Boc chemistry and the isodipeptide unit would be an effective method for the synthesis of many difficult peptides. Copyright © 2014 European Peptide Society and John Wiley&

ISSN:1075-2617    

DOI:10.1002/psc.2662

年代:2014

数据来源: WILEY

摘要:

We report a new method for multistep peptide synthesis on polymeric nanoparticles of differing sizes. Polymeric nanoparticles were functionalized via their temporary embedment into a magnetic inorganic matrix that allows multistep peptide synthesis. The matrix is removed at the end of the process for obtaining nanoparticles functionalized with peptides. The matrix‐assisted synthesis on nanoparticles was proved by generating various biologically relevant peptides. Copyright © 2014 European Peptide Society and John Wiley&Sons, L

ISSN:1075-2617    

DOI:10.1002/psc.2664

年代:2014

数据来源: WILEY

摘要:

Hepcidin is a cysteine‐rich peptide widely characterized in immunological processes and antimicrobial activity in several vertebrate species. Obviously, this hormone plays a central role in the regulation of systemic iron homeostasis. However, its role in camelids' immune response and whether it is involved in antibacterial immunity have not yet been proven. In this study, we characterized the Arabian camel hepcidin nucleotide sequence with an open reading frame of 252 bp encoding an 83‐amino acid preprohepcidin peptide. Eight cysteine key residues conserved in all mammalian hepcidin sequences were identified. The model structure analysis of hepcidin‐25 peptide showed a high homology structure and sequence identity to the human hepcidin. Two different hepcidin‐25 analogs manually synthesized by SPPS shared significant cytotoxic capacity toward the Gram‐negative bacteriumEscherichia coliAmerican Type Culture Collection (ATCC) 8739 as well as the Gram‐positive bacteriaBacillus subtilisATCC 11779 andStaphylococcus aureusATCC 6538in vitro. The three disulfide bridges hepcidin analog demonstrated bactericidal activity, againstB. subtilisATCC 11779 andS. aureusATCC 6538 strains, at the concentration of 15 μM (50 µg/ml) or above at pH 6.2. This result correlates with the revealed structural features suggesting that camel hepcidin is proposed to be involved in antibacterial process of innate immune response. Copyright © 2014 European Peptide Societ

ISSN:1075-2617    

DOI:10.1002/psc.2644

年代:2014

数据来源: WILEY

摘要:

Celiac disease (CD) is an autoimmune mediated disease with complex and multifactorial etiology. Gluten intake triggers a composite immune response involving T‐cells and B‐cells and leading to the secretion of autoantibodies if a genetic predisposition is present. Untreated CD patients show high levels of circulating autoantibodies directed to different auto‐antigens present in the intestinal mucosa. The most important auto‐antigen is the endomysial enzyme tissue transglutaminase (tTG). Both IgA and IgG antibody isotypes to tTG are known, but only the IgA antibodies demonstrate the highest disease specificity and thus are considered disease biomarkers. Because the pathogenicity and exact tTG binding properties of these autoantibodies are still unclear, the characterization of tTG antigenic domains is a crucial step in understanding CD onset and the autoimmune pathogenesis. Overlapping peptide libraries can be used for epitope mapping of selected protein portions to determine antigenic fragments contributing to the immunological activity and possibly develop innovative peptide‐based tools with high specificity and sensitivity for CD. We performed an epitope mapping study to characterize putative linear auto‐antigenic epitopes present in the tTG N‐terminal portion (1–230). A library of 23 overlapping peptides spanning tTG(1–230) was generated by Fmoc/tBu solid‐phase peptide synthesis and screened by immunoenzymatic assays employing patients' sera. The results indicate that four synthetic peptides, that is, Ac‐tTG(1–15)‐NH2, Ac‐tTG(41–55)‐NH2, Ac‐tTG(51–65)‐NH2, and Ac‐tTG(151–165)‐NH2, are recognized by IgA autoantibodies circulating in CD patients' sera. These results offer important insight on the nature of the antigen‐antibody interaction. Copyright © 2014 Eur

ISSN:1075-2617    

DOI:10.1002/psc.2650

年代:2014

数据来源: WILEY

摘要:

The Cu(I) catalyzed Huisgen 1,3‐dipolar azide‐alkyne cycloaddition (CuAAC) was applied for a nucleoside‐peptide bioconjugation. Systemin (Sys), an 18‐aa plant signaling peptide naturally produced in response to wounding or pathogen attack, was chemically synthesized as itsN‐propynoic acid functionalized analog (Prp‐Sys) using the SPPS. Next, CuAAC was applied to conjugate Prp‐Sys with 3′‐azido‐2′,3′‐dideoxythymidine (AZT), a model cargo molecule. 1,4‐Linked 1,2,3‐triazole AZT‐Sys conjugate was designed to characterize the spreading properties and ability to translocate of cargo molecules of systemin. CuAAC allowed the synthesis of the conjugate in a chemoselective and regioselective manner, with high purity and yield. The presence of Cu(I) ions generatedin situdrove the CuAAC reaction to completion within a few minutes without any by‐products. Under typical separation conditions of phosphate ‘buffer’ at low pH and uncoated fused bare‐silica capillary, an increasing peak intensity assigned to triazole‐linked AZT‐Sys conjugate was observed using capillary electrophoresis (CE) during CuAAC. CE analysis showed that systemin peptides are stable in tomato leaf extract for up to a few hours. CE‐ESI‐MS revealed that the native Sys and its conjugate with AZT are translocated through the tomato stem and can be directly detected in stem exudates. The results show potential application of systemin as a transporter of low molecular weight cargo molecules in tomato plant and of CE method to characterize a behavior of plant peptides and its analogs. Copyright © 2014 E

ISSN:1075-2617    

DOI:10.1002/psc.2653

年代:2014

数据来源: WILEY

摘要:

An extensive series of covalently linked small molecule–peptide adducts based on a terminally capped‐beta hairpin motif is reported. The constructs can be prepared by standard solid‐phase Fmoc chemistry with one to four peptide chains linked to small molecule hubs bearing carboxylic acid moieties. The key feature of interest is the precise, buried environment of the small molecule, and its rigid orientation relative to one or more short but fully structured peptide chain(s). Most of this study employs a minimalist nine residue ‘captide’, a cappedβ‐turn, but we illustrate general applicability to peptides which can terminate in a beta strand. The non‐peptide portion of these adducts can include nearly any molecule bearing one or more carboxylic acid groups. Fold‐dependent rigidity sets this strategy apart from the currently available bioconjugation methods, which typically engender significant flexibility between peptide and tag. Applications to catalyst enhancement, drug design, higher‐order assembly, and FRET calibration rulers are discussed. Copyright © 2014 European Peptide Society and J

ISSN:1075-2617    

DOI:10.1002/psc.2657

年代:2014

数据来源: WILEY

摘要:

Matrix metalloproteinases (MMPs) are a family of zinc‐dependent endopeptidases that degrade extracellular matrix components and play important roles in a variety of biological and pathological processes such as malignant tumor metastasis and invasion. In this study, we constructed carnosine–gallic acid peptide (CGP) to identify a better MMP inhibitor than carnosine. The inhibitory effects of CGP on MMP‐2 and MMP‐9 were investigated in the human fibrosarcoma (HT1080) cell line. As a result, CGP significantly decreased MMP‐2 and MMP‐9 expression levels without a cytotoxic effect. Moreover, CGP may inhibit migration and invasion in HT1080 cells through the urokinase plasminogen activator (uPA)–uPA receptor signaling pathways to inhibit MMP‐2 and MMP‐9. Based on these results, it appears that CGP may play an important role in preventing and treating several MMP‐2 and MMP‐9‐mediated health problems such as metastasis. Copyright © 2014 European Peptide Society

ISSN:1075-2617    

DOI:10.1002/psc.2658

年代:2014

数据来源: WILEY

摘要:

The antimicrobial 40‐amino‐acid‐peptide lucifensin was synthesized by native chemical ligation (NCL) usingN‐acylbenzimidazolinone (Nbz) as a linker group. NCL is a method in which a peptide bond between two discreet peptide chains is created. This method has been applied to the synthesis of long peptides and proteins when solid‐phase synthesis is imcompatible. Two models of ligation were developed: [15 + 25] Ala‐Cys and [19 + 21]His‐Cys. The [19 + 21] His‐Cys method gives lower yield because of the lower stability of 18‐peptide‐His‐Nbz‐CONH2peptide, as suggested by density functional theory calculation. Acetamidomethyl‐deprotection and subsequent oxidation of the ligated linear lucifensin gave a mixture of lucifensin isomers, which differed in the location of their disulfide bridges only. The dominant isomer showed unnatural pairing of cysteines [C1−6], [C3−5], and [C2−4], which limits its ability to formα‐helical structure. The activity of isomeric lucifensin towardBacillus subtilis,Staphylococcus aureus, andMicrococcus luteuswas lower than that of the natural lucifensin. The desired product native lucifensin was prepared from this isomer using a one‐pot reduction with dithiotreitol and subsequent air oxidation in slightly alkaline medium. Copyright © 2014

ISSN:1075-2617    

DOI:10.1002/psc.2663

年代:2014

数据来源: WILEY

摘要:

The solid‐phase synthesis, structural characterization, and biological evaluation of a small library of cancer‐targeting peptides have been determined in HepG2 hepatoblastoma cells. These peptides are based on the highly specific Pep42 motif, which has been shown to target the glucose‐regulated protein 78 receptors overexpressed and exclusively localized on the cell surface of tumors. In this study, Pep42 was designed to contain varying lengths (3–12) of poly(arginine) sequences to assess their influence on peptide structure and biology. Peptides were effectively synthesized by 9‐fluorenylmethoxycarbonyl‐based solid‐phase peptide synthesis, in which the use of a poly(ethylene glycol) resin provided good yields (14–46%) and crude purities>95% as analyzed by liquid chromatography–mass spectrometry. Peptide structure and biophysical properties were investigated using circular dichroism spectroscopy. Interestingly, peptides displayed secondary structures that were contingent on solvent and length of the poly(arginine) sequences. Peptides exhibited helical and turn conformations, while retaining significant thermal stability. Structure–activity relationship studies conducted by flow cytometry and confocal microscopy revealed that the poly(arginine) derived Pep42 sequences maintained glucose‐regulated protein 78 binding on HepG2 cells while exhibiting cell translocation activity that was contingent on the length of the poly(arginine) strand. In single dose (0.15 mM) and dose‐response (0–1.5 mM) cell viability assays, peptides were found to be nontoxic in human HepG2 liver cancer cells, illustrating their potential as safe cancer‐targeting delivery agents. Copyright © 2014 European Peptide

ISSN:1075-2617    

DOI:10.1002/psc.2665

年代:2014

数据来源: WILEY

ISSN:1075-2617    

DOI:10.1002/psc.2564

年代:2014

数据来源: WILEY