摘要:

AbstractAs proline plays an important role in biologically active peptides, many analogues of this residue have been developed to modulate the proportion ofcisandtransconformers. A correlation between the pyrrolidine ring shape and structural properties of proline has been established. Diketopiperazine (DKP) is the model of choice to study the influence of the proline ring modification. In this contribution, cyclo(Gly‐Pro) and two analogues cyclo(Sip‐Pro) and cyclo(Thz‐Pro) have been studied with proton NMR. We showed that both analogues with heteroatoms in γ position, silicon and sulfur respectively, display a more rigid five‐member ring. The usual flexibility of proline ring is restrained in both cases and only the two Cβ‐exo and Cβ‐endo conformations are observed. Copyright © 2006 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.767

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractSince phosphatidylserine (PS) is known to translocate to the external face of the plasma membrane when the cell membrane becomes disordered, we decided to focus our attention on PS as a target molecule for gene delivery. In this paper, the novel peptide Td3701 was designed, synthesized, and characterized for its physico‐chemico‐biological properties. Td3701 simultaneously exhibited both characters as a DNA carrier and a sensor probe for active targeting, which seemed to be triggered by structural changes in the presence of PS. This is a very unique character among nonviral vectors, and it is believed that Td3701 could be used for selective gene delivery. Copyright © 2006 European Peptide Society and John Wiley&Sons,

ISSN:1075-2617    

DOI:10.1002/psc.768

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractA rapid and efficient microwave‐assisted solid‐phase synthesis method is described for the preparation of the nonapeptide WDTVRISFK, using conventional Fmoc/Butorthogonal protection strategy. The synthesis protocol is based on the use of cycles of pulsed microwave irradiation with intermittent cooling of the reaction during the removal of the Fmoc protecting group and during the coupling. The desired nonapeptide was obtained in highest yield and purity by employing MicroKan technology. The chemical reactions were carried out in a single‐mode microwave reactor, equipped with a fiber‐optic probe to monitor the reaction temperature continuously. Copyright © 2006 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/psc.771

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractThe structure of a highly potent Ser14Gly analog of antiAlzheimer peptide, Humanin, was examined by circular dichroism (CD). The secondary structure is more disordered in water than in phosphate‐buffered saline (PBS). The peptide structure in water is little dependent on both peptide concentration and temperature. On the contrary, the peptide structure was significantly different in PBS from the structure in water, which is more apparent at a higher peptide concentration and temperature. The observed different structure in PBS appears to be due to self‐association of the peptide, which is enhanced by elevated temperature and, hence, via hydrophobic interactions. The wild‐type Humanin also behaved similarly, i.e., it assumed a disordered structure in water but underwent conformational changes in PBS. Although high peptide concentrations for CD measurements are not encounteredin vivo, the results suggest the tendency of the peptide to interact hydrophobically with other structures as well as with itself. Copyright © 2006 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/psc.773

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractAntibacterial peptides have been isolated from a wide range of species. Some of these peptides act on microbial membranes, disrupting their barrier function. With the increasing development of antibiotic resistance by bacteria, these antibacterial peptides, which have a new mode of action, have attracted interest as antibacterial agents. To date, however, few effective high‐throughput approaches have been developed for designing and screening peptides that act selectively on microbial membranes.In vitrodisplay techniques are powerful tools to select biologically functional peptides from peptide libraries. Here, we used the ribosome display system to form peptide‐ribosome‐mRNA complexesin vitrofrom nucleotides encoding a peptide library, as well as immobilized model membranes, to select specific sequences that recognize bacterial membranes. This combination of ribosome display and immobilized model membranes was effective as anin vitrohigh‐throughput screening system and enabled us to identify motif sequences (ALR, KVL) that selectively recognized the bacterial membrane. Owing to host toxicity, it was not possible to enrich any sequence expected to show antimicrobial activity using anotherin vitrosystem, e.g. phage display. The synthetic peptides designed from these enriched motifs acted selectively on the bacterial model membrane and showed antibacterial activity. Moreover, the motif sequence conferred selectivity onto native peptides lacking selectivity, and decreased mammalian cell toxicity of native peptides without decreasing their antibacterial activity. Copyright © 2006 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/psc.774

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractEdeines are pentapeptide amide antibiotics composed of four nonprotein amino acids, glycine, and polyamine. They exhibit antimicrobial and immunosuppressive activities and are universal inhibitors of translation. Moreover, it was proven that the free ionizable carboxy group in the (2R, 6S, 7R)‐2,6‐diamino‐7‐hydroxyazelaic acid moiety is not essential for biological activity of these compounds. In this paper we describe the synthesis of four novel edeine A and D analogues in which the above‐mentioned acid residue was replaced with the (3R, 4S)‐ or (3S, 4S)‐4,5‐diamino‐3‐hydroxypentanoic acid moiety. In one compound we also introduced into molecule the 3‐N,N‐dimethyl derivative of (S)‐2,3‐diaminopropanoic acid to prevent the transpeptidation process, which results in the loss of biological activity of α‐isomers of edeines. All peptides were synthesized applying the active ester and azide methods and on the basis of the coupling of suitableN‐terminal tripeptides with properC‐terminal dipeptide amides. The activities of the newly obtained edeine analogues against selected strains of bacteria and fungi are also presented. Copyright © 2006 European Pepti

ISSN:1075-2617    

DOI:10.1002/psc.775

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractAlternative RGD mimetics—with the exception of glycine—c(Arg‐Asp)1, c(Arg‐Glu)2and c[Arg‐Asp(Phe‐OH)]3were synthesized. The DKPs were prepared on solid phase with orthogonal protection allowing further derivatization in solution. During solution phase cyclization in NH3/methanol, the side chain benzyl ester group of H‐Arg(Tos)‐Asp(OBzl)‐OMe and H‐Arg(Tos)‐Glu(OBzl)‐OMe suffer transesterification, while β‐t‐butyl or β‐cyclohexyl esters are stable under the same conditions. In spite of the simple structure, all compounds bind selectively to the αvβ3integrin receptor,3showing the highest affinity with an IC50value of 0.74 µMvalue. On the other hand only3binds with measurable activity to the αIIbβ3receptor (IC50159 µM). The binding affinities seem to be in accordance with the distances between the arginine guanidino and the aspartic acid carboxyl group in extended conformation determined by semiempirical geometry optimization. Copyright © 2006 European Pe

ISSN:1075-2617    

DOI:10.1002/psc.776

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractA novel group of [(4‐, 5‐ or 8)‐hydroxy‐9,10‐anthraquinone‐1‐yl]‐(tuftsin or retro‐tuftsin) acids and methyl esters has been synthesized as potential anticancer compounds. The corresponding protected tuftsin or retro‐tuftsin derivatives were also synthesized. We hope that combining compounds of different mechanisms of action will improve their clinical properties, and that our new analogues will be much more effective against multidrug‐resistant tumour cell lines. Copyright © 2006 European Peptide Society an

ISSN:1075-2617    

DOI:10.1002/psc.777

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY