摘要:

AbstractA PEGA‐resin was derivatized with a 3:1 mixture of hydroxymethyl benzoic acid and Fmoc‐Lys(Boc)‐OH and the fluorogenic substrate Ac‐Y(NO2)KLRFSKQK(Abz)–PEGA was assembled on the lysine using the active ester approach. Following esterification of the hydroxymethyl benzoic acid with Fmoc‐Val‐OH a library XXX‐k/r‐XXXV containing approximately 200,000 beads was assembled by split synthesis. The resulting ‘one bead, two peptides’ library was subjected to extensive hydrolysis with cruzipain. One hundred darker beads were isolated and the 14 most persistently dark beads were collected and sequenced. The putative inhibitor peptides and several analogues were synthesized and found to be competitive μMto nMinhibitors of cruzipain in solution. The inhibitory activity was found to be unspecific to cruzipain when compared with cathepsins B and L and specific when compared with kallikrein. One of the inhibitors was docked into the active site of the cathepsin B and was found most probably to bind to the enzyme cavity in an unusual manner, owing to the insertedD‐amino acid residue. © 1998 European Peptide Society

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<83::AID-PSC124>3.0.CO;2-Z

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractContinuing the studies on structural requirements of bradykinin antagonists, it has been found that analogues with dehydrophenylalanine (ΔPhe) or its ring‒substituted analogues (ΔPhe(X)) at position 5 act as antagonists on guinea pig pulmonary artery, and on guinea pig ileum. Because both organs are considered to be bradykinin B2receptor tissues, the analogues with ΔPhe or ΔPhe(X) at position 5, but without any replacement at position 7, seem to represent a new structural type of B2receptor antagonist. All the analogues investigated act as partial antagonists; they inhibit the bradykinin‒induced contraction at low concentrations and act as agonists at higher concentrations. Ring substitutions by methyl groups or iodine reduce both the agonistic and antagonistic activity. Only substitution by fluorine gives a high potency. Incorporation of ΔPhe into different representative antagonists with key modifications at position 7 does not enhance the antagonist activity of the basic structures, with one exception. Only the combination of ΔPhe at position 5 withDPhe at position 7 increases the antagonistic potency on guinea pig ileum by about one order of magnitude. Radio‒ligand binding studies indicate the importance of position 5 for the discrimination of B2receptor subtypes. The binding affinity to the low‒affinity binding site (KL) was not significantly changed by replacement of Phe by ΔPhe. In contrast, ring‒methylation of ΔPhe results in clearly reduced binding to KL. The affinity to the high‒affinity binding site (KH) was almost unchanged by the replacement of Phe in position 5 by ΔPhe, whereas the analogue with 2‒methyl‒dehydrophenylalanine completely failed to detect the KH‒site. The peptides were synthesized on the Wang‒resin according to the Fmoc/Butstrategy using Mtr protection for the side chain of Arg. The dehydrophenylalanine analogues were prepared by a strategy involving PyBop couplings of the dipeptide unit Fmoc‒Gly‒ΔPhe(X)‒OH to resin‒bound fragments. © 1998 European Pe

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<92::AID-PSC131>3.0.CO;2-8

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractThe conformation of a [15]‐peptide (H‐VKAETRLNPDLQPTE‐NH2) from VP2 of rhinovirus HRV2 complexed with a Fab fragment was previously shown by X‐ray crystallographic studies to be similar to the one found in the corresponding region of HRV1A. Antibodies raised against this peptide bind to and neutralize HRV2. In order to identify structural features preserved in solution that may explain the ability of this short peptide to mimic the structure of the protein surface, the peptide has been studied by NMR in aqueous solution as well as under denaturing conditions.The peptide is shown to be a random coil in solution. However, the sequence forming a 310helix in the complex is biased into a helical conformation according to NOE intensity data as well as from urea and pH titrations. This sequence adopts the same conformation in an unrelated protein. NOE data suggest that a β‐turn found in the complex may be sampled in solution. Also, Glu4, interacting with Arg6 in the crystal, has a reduced pKavalue in solution. It is concluded that the local structure present in the random coil state of VP2(156–170) contains enough information to direct the production of antibodies that bind to and neutralize HRV2. © 1998 European Peptide Society and John Wi

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<101::AID-PSC133>3.0.CO;2-C

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractSix peptides have been isolated and characterized from the dorsal glands of the tree frogLitoria genimaculata. One of these is the known hypotensive peptide caerulein; the others have been named maculatins. The amino acid sequences of the maculatin peptides have been determined using a combination of fast atom bombardment mass spectrometry and automated Edman sequencing. Four of the maculatin peptides show antibiotic activity, with maculatin 1.1 [GLFGVLAKVAAHVVPAIAEHF(NH2;)] showing the most pronounced activity, particularly against Gram‐positive organisms. Maculatin 1.1 resembles the known caerin 1 antibiotic peptides, except that four of the central amino acid residues (of the caerin 1 system) are missing in maculatin 1.1. A comparison of the antibiotic activity of maculatin 1.1 with those of caerin 1.1 is reported. ©1998 European Peptide Society and John Wiley&Sons, L

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<111::AID-PSC134>3.0.CO;2-8

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractGelsolin is a protein that severs and caps actin filaments. The two activities are located in the N‐terminal half of the gelsolin molecules. Severing and subsequent capping requires the binding of domains 2 and 3 (S2–3) to the side of the filaments to position the N‐terminal domain 1 (S1) at the barbed end of actin (actin subdomains 1 and 3). The results provide a structural basis for the gelsolin capping mechanism. The effects of a synthetic peptide derived from the sequence of a binding site located in gelsolin S2 on actin properties have been studied. CD and IR spectra indicate that this peptide presented a secondary structure in solution which would be similar to that expected for the native full length gelsolin molecule. The binding of the synthetic peptide induces conformational changes in actin subdomain 1 and actin oligomerization. An increase in the polymerization rate was observed, which could be attributed to a nucleation kinetics effect. The combined effects of two gelsolin fragments, the synthetic peptide derived from an S2 sequence and the purified segment 1 (S1), were also investigated as a molecule model. The two fragments induced nucleation enhancement and inhibited actin depolymerization, two characteristic properties of capping. In conclusion, for the first time it is reported that the binding of a small synthetic fragment is sufficient to promote efficient capping by S1 at the barbed end of actin filaments. ©1998 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<116::AID-PSC135>3.0.CO;2-R

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractProtein disulphide isomerase is an enzyme that catalyses disulphide redox reactions in proteins. In this paper, fluorogenic and interchain disulphide bond containing peptide libraries and suitable substrates, useful in the study of protein disulphide isomerase, are described. In order to establish the chemistry required for the generation of a split‐synthesis library, two substrates containing an interchain disulphide bond, a fluoroescent probe and a quencher were synthesized. The library consists of a Cys residue flanked by randomized amino acid residues at both sides and the fluoroescent Abz group at the amino terminal. All the 20 natural amino acids except Cys were employed. The library was linked to PEGA‒beads via methionine so that the peptides could be selectively removed from the resin by cleavage with CNBr. A disulphide bridge was formed between the bead‒linked library and a peptide containing the quenching chromophore (Tyr(NO2)) and Cys(pNpys) activated for reaction with a second thiol. The formation and cleavage of the interchain disulphide bonds in the library were monitored under a fluoroescence microscope. Substrates to investigate the properties of protein disulphide isomerase in solution were also synthesized. © 1998 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<128::AID-PSC137>3.0.CO;2-E

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY

摘要:

AbstractAn efficient procedure is described for the synthesis ofNα‐Fmoc‐O‐monobenzyl phosphonotyrosine from the corresponding dibenzyl derivative by monodebenzylation in the presence of sodium iodide. A simple work up procedure removes the by‐products and the monobenzylated phosphono product is obtained in high yield. © 1998 European Peptide Society and John Wiley&

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199804)4:2<138::AID-PSC150>3.0.CO;2-W

出版商:John Wiley&Sons, Ltd.    

年代:1998

数据来源: WILEY