摘要:

Purification of pluripotent stem cell (PSC)‐derived cardiomyocytes is critical for the application of cardiomyocytes both in clinical and basic research. Finding a specific cell marker is a promising method for purifying induced cells. The present study employed phage display technology to search for particular cell markers that could bind specifically to PSC‐derived cardiomyocytes. After three rounds of biopanning, several peptides were obtained. The ELISA results show the no. 3 sequence peptide (QPFTTSLTPPAR), and other four sequences having a consensus motif [SS(Q)PPQ(S)], no. 9, 11, 14, and 10, have relatively high affinity and specificity to cardiomyocytes. Immunofluorescence confirmed that the selected peptides could bind specifically to the PSC‐derived cardiomyocytes. Competition tests with chemically synthesized peptides revealed the binding ability was caused by the peptide itself. Western blot analysis proved the phages were both bound to two 17 kDa cardiomyocyte membrane proteins and the no. 9 sequence showed a 55 kDa protein that was not observed in the no. 3 sequence. These results suggest that the selected peptides specifically target receptors on PSC‐derived cardiomyocyte membranes. The results will pave the way for further studies of cell surface markers and their applications, such as labeling, purification, and as vehicles for drug delivery. Copyright © 2011 European Peptide Society and John Wil

ISSN:1075-2617    

DOI:10.1002/psc.1401

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

De novodesign of peptides and proteins has recently surfaced as an approach for investigating protein structure and function. This approach vitally tests our knowledge of protein folding and function, while also laying the groundwork for the fabrication of proteins with properties not precedented in nature. The success relies heavily on the ability to design relatively short peptides that can espouse stable secondary structures. To this end, substitution withα,β‐didehydroamino acids, especiallyα,β‐didehydrophenylalanine (ΔzPhe), comes in use for spawning well‐defined structural motifs. Introduction of ΔPhe inducesβ‐bends in small and 310‐helices in longer peptide sequences. The present work aims to investigate the effect of nature and the number of amino acids interspersed between two ΔPhe residues in two model undecapeptides, Ac‐Gly‐Ala‐ΔPhe‐Ile‐Val‐ΔPhe‐Ile‐Val‐ΔPhe‐Ala‐Gly‐NH2(I) and Boc‐Val‐ΔPhe‐Phe‐Ala‐Phe‐ΔPhe‐Phe‐Leu‐Ala‐ΔPhe‐Gly‐OMe (II). Peptide I was synthesized using solid‐phase chemistry and characterized using circular dichroism spectroscopy. Peptide II was synthesized using solution‐phase chemistry and characterized using circular dichroism and nuclear magnetic resonance spectroscopy. Peptide I was designed to examine the effect of incorporatingβ‐strand‐favoring residues like valine and isoleucine as spacers between two ΔPhe residues on the final conformation of the resulting peptide. Circular dichroism studies on this peptide have shown the existence of a 310‐helical conformation. Peptide II possesses three amino acids as spacers between ΔPhe residues and has been reported to adopt a mixed 310/α‐helical conformation using circular dichroism and nuclear magnetic resonance s

ISSN:1075-2617    

DOI:10.1002/psc.1402

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

Tyrosinase plays a critical role in the early stages of the melanin synthetic pathway by catalyzing the oxidation of the substrate. Therefore, tyrosinase inhibitors have been intensively studied in both cosmetic and food industries to develop hypopigmentary agents and prevent enzymatic browning in food. Previously, we reported that kojic acid–amino acid amide (KA‐AA‐NH2) showed enhanced tyrosinase inhibitory activity compared with kojic acid alone, but this was not observed in a cell test because of poor cell permeability. To enhance cell permeability, we prepared copper and zinc complexes of KA‐AA‐NH2and characterized them using FT‐IR spectroscopy, ESI‐MS spectrometry, and inductively coupled plasma analysis. We then showed that KA‐AA‐NH2copper complexes exhibited melanogenesis inhibitory activity in Mel‐Ab cells. Copyright © 2011 European Peptide Society and

ISSN:1075-2617    

DOI:10.1002/psc.1404

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

Thermal stability of theα‐helix conformation of melittin in pure ethanol and ethanol–water mixture solvents has been investigated by using NMR spectroscopy. With increase in water concentration of the mixture solvents (from 0 wt% to ~71.5 wt%) as well as temperature (from room temperature to 60 °C), the intramolecular hydrogen bonds formed in melittin are destabilized and theα‐helix is partially uncoiled. Further, the hydrogen bonds are found to be more thermally stable in pure ethanol than in pure methanol, suggesting that their stability is enhanced with increase in the size of the alkyl groups of alcohol molecules. Copyright © 2011 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.1405

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

Pemetrexed (Pem) is a novel antimetabolite type of anticancer drug that demonstrated promising clinical activity in a wide variety of solid tumors, including non‐small cell lung carcinoma and malignant pleural mesothelioma. It inhibits enzymes involved in the folate pathway, for which the presence of its free carboxylic groups is necessary. The heteroaromatic ring system of Pem has a modifiable amino group, which opens a possibility to apply a new strategy to conjugate Pem to carrier molecules. Considering this as well as the necessity of untouched carboxylic groups of Pem in the new conjugates, we developed a new synthesis strategy. Here, we describe the synthesis and the characterization of new Pem‐peptide conjugates in which cell‐penetrating octaarginine or/and lung‐targeting H‐Ile‐Glu‐Leu‐Leu‐Gln‐Ala‐Arg‐NH2peptide is attached to the drug by thioether bond. The conjugates characterized by RP‐HPLC and MS exhibited cytostatic effectin vitroon non‐small cell lung carcinoma as well as on human leukemia cell lines. The IC50values of the conjugates were similar, but the conjugates with H‐Ile‐Glu‐Leu‐Leu‐Gln‐Ala‐Arg‐NH2sequence were slightly more effective. Our data show that thein vitrocytostatic effect of the free Pem was essentially maintained after conjugation with cell‐penetrating or cell‐targeting peptides. Thus, the conjugation strategy reported could lead to the development of a new generation of active Pem conjugates. Copyright © 2011 E

ISSN:1075-2617    

DOI:10.1002/psc.1407

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

pVEC is a cell‐penetrating peptide derived from the murine vascular endothelial‐cadherin protein. To evaluate the potential ofpVEC as antimicrobial peptide (AMP), we synthesizedpVEC and its analogs with Trp and Arg/Lys substitution, and their antimicrobial and lipopolysaccharide (LPS)‐neutralizing activities were investigated.pVEC and its analogs displayed a potent antimicrobial activity (minimal inhibitory concentration: 4–16 μM) against Gram‐positive and Gram‐negative bacteria but no or less hemolytic activity (less than 10% hemolysis) even at a concentration of 200 μM. These peptides induced a near‐complete membrane depolarization (more than 80%) at 4 μM againstStaphylococcus aureusand a significant dye leakage (35–70%) from bacterial membrane‐mimicking liposome at a concentration as low as 1 μM. The fluorescence profiles ofpVEC and its analogs in dye leakage from liposome and membrane depolarization were similar to those of a frog‐derived AMP, magainin 2. These results suggest thatpVEC and its analogs kill bacteria by forming a pore or ion channel in the cytoplasmic membrane.pVEC and its analogs significantly inhibited nitric oxide production or tumor necrosis factor‐α release in LPS‐stimulated mouse macrophage RAW264.7 cells at 10 to 50 μM, in which RAW264.7 were not damaged. Taken together, our results suggest thatpVEC and its analogs with potent antimicrobial and LPS‐neutralizing activities can serve as AMPs for the treatment of microbial infection and sepsis. Copyright © 2011 Europea

ISSN:1075-2617    

DOI:10.1002/psc.1408

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY

摘要:

Sublancin is an S‐linked glycopeptide produced byBacillus subtilis168 and consists of 37 amino acid residues with two disulfide bonds. In this study, we synthesized sublancin by Fmoc‐based solid‐phase peptide synthesis and chemoselective disulfide formation reactions. Copyright © 2011 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/psc.1406

出版商:John Wiley&Sons, Ltd    

年代:2011

数据来源: WILEY