摘要:

Abstractβ‐defensins are a large family of multiple disulfide‐bonded peptides occurring in mammals and birds. They play an important role in the innate immune system, directly killing microbial organisms. Recent research has demonstrated that β‐defensins are important for other biological functions beyond antimicrobial effects, including inhibition of viral infection, interaction with Toll‐like receptors, chemotactic effects, and sperm function. The corresponding broad spectrum of activities makes this peptide class an important subject and tool in immunologic research. In this review, we summarize the current status of the routes to obtain synthetic β‐defensins, their major structural properties and structure–activity relationship. Copyright © 2006 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.749

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractThe closely related neuropeptides orexin A and orexin B mediate their actions, including the regulation of sleep and appetite, by the activation of the orexin 1 and 2 receptors. To elucidate the structural prerequisites for receptor activation and subtype selectivity, we performed multiple amino acid substitutions within the sequence of orexin A and human orexin B‐(6‐28)‐peptide and analyzed their solution structures by CD spectroscopy and their activity at both receptors in Ca2+mobilization assays. For orexin A, we showed that the basic amino acids within the segment of residues 6–14 were important for the activation of both receptors. Furthermore, we showed that the restriction via disulfide bonds is not required to maintain the active structure of orexin A. The kink region of h orexin B has been shown to be important for Ox2R selectivity, which is not mediated by the restriction of the turn structure. Additionally, we showed that no particular secondary structure is required for receptor subtype selectivity. Copyright © 2005 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/psc.716

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractIn this work, new putative epitopes located in nonstructural proteins of GBV‐C/HGV were synthesized using solid‐phase chemistry for their use in immunoassays. The antigens were obtained in linear, chimeric and cyclic forms with the main aim of improving the sensitivity of the enzyme immunoassays. Our results showed, on one hand, that the combination of different antigens seems to be necessary to ensure good sensitivity and more specificity and, on the other hand, that cyclic compounds show higher ability to recognize anti‐GBV‐C/HGV antibodies than its parent peptide. Furthermore, CD and FTIR have been used in conjunction to characterize the conformational changes therein with synthetic constructs that could explain their different antigenicity. Copyright © 2005 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/psc.719

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractThe microheterogeneous alamethicin F30 (ALM F30) isolated from the fermentation ofTrichoderma viridestrain NRRL 3199 was analyzed by nonaqueous capillary electrophoresis coupled to electrospray ion‐trap mass spectrometry (ESI‐IT‐MS) and electrospray time‐of‐flight mass spectrometry (ESI‐TOF‐MS). Tandem ESI‐IT‐MS was used for elucidation of the amino acid sequence based on the fragmentation pattern of selected parent ions. The MS/MS spectra using the [M + 3H]3+or [M + 2H]2+ions as precursor ions displayed the respective b‐ and the y‐type fragments resulting from cleavage of the particularly labile Aib–Pro bond. The MS3of these fragments generated the b acylium ion series, as well as internal fragment ion series. Eleven amino acid sequences were identified, characterized by the exchange of Ala to Aib in position 6, Gln to Glu in positions 7 or 19 as well as the loss of theC‐terminal amino alcohol. In addition, two truncated pyroglutamyl peptaibols were found. Overall, seven new sequences are reported compared to earlier LC–MS studies. The composition of the components was confirmed by on‐line ESI‐TOF‐MS detection. Mass accuracy well below 5 ppm was observed. Quantification of the individual components was achieved by a combination of UV and TOF‐MS detection. Copyright © 2005 European Pept

ISSN:1075-2617    

DOI:10.1002/psc.720

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractProtein glycation through Maillard reaction (MR) is a fundamental reaction both in foods and in the human body. The first step of the reaction is the formation of Amadori product (AP) that is converted into intermediate and advanced MR products during reaction development. Although the MR is not an enzymatic reaction, a certain degree of specificity in the glycation site has been observed. In the present study, we have monitored the glycation of different lysine‐containing dipeptides to evaluate the influence on the NH2reactivity of the neighboring amino acid.Lysine dipeptides were reacted with glucose, galactose, lactose and maltose. The formation and identification of glycated compounds were monitored by mass spectrometry (MALDI‐TOF and ESI‐MS/MS) and by HPLC of their Fmoc derivatives. MS/MS analysis showed that the glucose APs formed on dipeptides have a characteristic fragmentation pattern: the fragment at [M − 84]+due to the formation of pyrylium and furylium ion is mainly present in the monoglucosylated form, while the [M − 162]+and the [M − 324]+are more evident in the fragmentation pattern of the diglucosylated forms.The nature of the vicinal amino acids strongly affects lysine reactivity towards the different carbohydrates: the presence of hydrophobic residues such as Ile, Leu, Phe strongly increases lysine reactivity. Contrasting results were obtained with basic residues. The Lys‐Arg dipeptide was among the most reactive while the Lys‐Lys was not. Copyright © 2005 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.722

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractCD studies on tetrazole analogues of opioid peptides show that peptides sharing the sameN‐terminal sequence, H‐TyrΨ[CN4]Gly‐, give very large Cotton effects of the Tyr side chain in the near‐UV region. CD spectra of five such peptides: H‐TyrΨ[CN4]Gly‐Gly‐Phe‐Leu‐OH (I), H‐TyrΨ[CN4]Gly‐Phe‐Pro‐Gly‐Pro‐Ile‐NH2(II), H‐TyrΨ[CN4]Gly‐Phe‐Pro‐NH2(III), H‐TyrΨ[CN4]Gly‐Phe‐Gly‐Tyr‐Pro‐Ser‐NH2(IV), and H‐TyrΨ[CN4]Gly‐Phe‐Asp‐Val‐Val‐Gly‐NH2(V), and two others for comparison: H‐Tyr‐GlyΨ[CN4]Gly‐Phe‐Leu‐OH (VI) and H‐TyrΨ[CN4]Ala‐Phe‐Gly‐Tyr‐Pro‐Ser‐NH2(VII), were measured in methanol, 2,2,2‐trifluoroethanol, and water at different pH values. The spectra show that the conformations of the Tyr1residue in peptidesI–Vare very similar in all solvents used but differ distinctly from those observed forVIandVII. Strong Tyr bands in the aromatic region result probably from the rigid structure of the commonN‐terminal part of peptidesI–V. These bands are weaker forIV, which maybe due to the presence of a second Tyr residue in that peptide, giving an opposite contribution to the CD spectrum as that arising from Tyr1. It seems that the rigid structure of theN‐terminal part ofI–Vresults from the interaction of the Tyr1side chain and the tetrazole ring. The CD bands of the Tyr residues ofVIandVIIare much smaller than those ofI–Vin all solvents, exceptVIIin trifluoroethanol (TFE) where Tyr bands comparable in intensity to those ofI–Vare observed. This spectral property may derive from the same sign contributi

ISSN:1075-2617    

DOI:10.1002/psc.723

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY

摘要:

AbstractA direct method for the preparation of phosphonamidate‐ and phosphonate‐linked phosphonopeptides has been developed. Using this method, both phosphonopeptides were prepared in acceptable yields directly from simple and commercially available chemicals in one‐pot reactions of benzyl carbamate, aldehydes, and methyl dichlorophosphite, followed by aminolysis with amino acid esters or alcoholysis with hydroxy esters. Copyright © 2005 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/psc.727

出版商:John Wiley&Sons, Ltd.    

年代:2006

数据来源: WILEY