摘要:

AbstractSynthetic, biological and conformational studies on the insect neuropeptide proctolin (Arg‐Tyr‐Leu‐Pro‐Thr) and some of its analogues are reviewed. Copyright © 1999 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<533::AID-PSC225>3.0.CO;2-9

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY

摘要:

AbstractThe lipophilic, chiral, Cα‐methylated α‐amino acidL‐(αMe)Aoc (2‐methyl‐2‐amino‐octanoic acid) was prepared using a chemo‐enzymatic approach. Two series of terminally protected model peptides, from dimer through to hexamer, containingL‐(αMe)Aoc in combination with either Gly or Aib, were synthesized by solution methods and were fully characterized. A solution conformational analysis, based on FT‐IR absorption,LH‐NMR and circular dichroism (CD) techniques, was performed with the aim at determining the preferred conformation of this novel amino acid and the relationship between chirality at its α‐carbon atom and screw sense of the helix that is formed. The results obtained strongly support the view thatL‐(αMe)Aoc favours the formation of theright‐handed 310‐helical conformation. Copyright © 1999 European Pept

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<547::AID-PSC221>3.0.CO;2-8

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY

摘要:

AbstractA solid phase approach has been used to synthesize a large branched disulphide peptide from IgG Fc, Ac‐F‐C*‐A‐K‐V‐N‐N‐K‐D‐L‐P‐A‐P‐I‐E‐K(Ac‐E‐L‐L‐G‐G‐P‐S‐V‐F)‐C*‐I‐NH2. This peptide combines the lower hinge region of IgG and a proximal β‐hairpin loop, both implicated in binding to FcγRI. Solid phase Tl(tfa)3cyclization of the linear branched peptide resulted in a poor yield of cyclic hinge–loop peptide (11%) most likely due to steric hindrance caused by the branch. However, if addition of the branch was preceded by solid phase Tl(tfa)3cyclization of the loop, the yield was excellent at 75%. Cyclic hinge–loop peptide was active in displacing IgG2a from FcγRI expressed on monocyte cell lines with an IC50of 40 μM, whereas the linear form of this peptide was inactive. The Fc hinge–loop peptide demonstrates the potential for a non‐mAb high affinity, immunomodulatory ligand for Fcγ

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<555::AID-PSC220>3.0.CO;2-G

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY

摘要:

AbstractPrevious studies have shown that acylated plasma and milk proteins with increased negative charge, derived from various animal and human sources, are potent anti‐HIV compounds. The antiviral effects seemed to correlate positively with the number of negative charges introduced into the various polypeptides: proteins with a high content of basic amino acids in which all of the available εNH2groups were anionized yielded the most potent anti‐HIV compounds. It remained unclear however whether the total net negative charge of the various derivatized proteins, or rather the charge density on the protein backbone, is essential for the observed anti‐HIV activity. Earlier studies have shown that acylated albumins preferentially block the process of HIV/cell fusion through binding to the HIV envelope proteins gp120 and gp41 as well as to the cell surface of the HIV target cells. Some of these polyanionic proteins have been shown to interfere also with the gp120–CD4 mediated virus/cell binding. The relative contribution of these effects to the anti‐HIV activity may depend both on the total negative charge introduced as well as the hydrophobicity of the acylating reagent added to the particular proteins. In this study we show that the higher the charge density of the derivatized proteins, the more potent their HIV replication inhibiting effects are. In contrast, the addition of positive charge to the studied plasma and milk proteins through amination resulted in a reduced anti‐HIV activity but a clearly increased anti‐HCMV activity, with IC50values in the low micromolar concentration range. Interestingly, native lactoferrin (Lf) was antivirally active against both HIV and HCMV. Acylation or amination of Lf increased the anti‐HIV and anti‐HCMV activity, respectively. TheN‐terminal portion of Lf appeared essential for its anti‐HCMV effect:N‐terminal deletion variants of human Lf were less active against HCMV. Circular dichroism of the modified proteins showed that the secondary structure of the tested proteins was only moderately influenced by acylation and/or covalent attachment of drugs, making these (derivatized) proteins useful candidates as antiviral agents and/or intrinsically active drug carriers. The relatively simple chemical derivatization as well as the abundant sources of blood plasma and milk proteins provides attractive opportunities for the preparation of potent and relatively cheap antiviral agents for systemic or local applications. Copyright © 1999 European Peptide Society

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<563::AID-PSC226>3.0.CO;2-3

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY

摘要:

AbstractThe synthesis of three hydrophobic peptides, which are partial sequences of thioredoxin, on a newly developed, flexible 1,6‐hexanediol diacrylate cross‐linked polystyrene, in good yield and purity, is described. Copyright © 1999 European Peptide Society and John Wiley&Sons,

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<577::AID-PSC227>3.0.CO;2-O

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY

摘要:

AbstractThe non‐codable amino acidO‐amino‐serine, Ams, has been prepared in bothL‐ andD‐forms as the orthogonally protected derivative, Fmoc‐Ams(Boc)‐OH (1and2). This new amino acid derivative is useful for chemoselective ligations. Under acidic conditions and in the presence of all other common amino acid functionalities, the oxyamine function selectively forms oxime linkages with aldehydes. The Ams residue has been incorporated into both ends of the peptide sequence Asp‐Leu‐Trp‐Gln‐Lys using standard SPPS. The deprotected peptide has been used for chemical ligation to afford a peptide dimer as well as a glycopeptide. Ams racemization was found to be negligible, as monitored by HPLC separation of Ams dipeptide diastereomers. Copyright © 1999 European Peptide Society an

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199912)5:12<582::AID-PSC228>3.0.CO;2-Z

出版商:John Wiley&Sons, Ltd.    

年代:1999

数据来源: WILEY