New synthetic siderophores and Their β-Lactam conjugates based on diamino acids and dipeptides
摘要:
Linking of siderophores to antibiotics improves the penetration and therefore increases the antibacterial activity of the antibiotics. We synthesized the acylated catecholates and hydroxamates as siderophore components for antibiotic conjugates to reduce side effects of unprotected catecholate and hydroxamate moieties. In this paper, we report on bis- and tris-catecholates and mixed catecholate hydroxamates based on diamino acids or dipeptides. These compounds were active as siderophores in a growth promotion assay under iron limitation. Most of the conjugates with beta-lactams showed high in vitro activity against Gram-negative bacteria especially Pseudomonas acruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia mareeseems and Stenotrophomonas maltophilia. The compounds with enhanced antibacterial activity use active iron uptake routes to penetrate the bacterial outer membrane barrier, demonstrated by assays with mutants deficient in components of the iron transport system. Correlation between chemical structure and biological activity was studied. (C) 2002 Published by Elsevier Science Ltd.
New synthetic siderophores and Their β-Lactam conjugates based on diamino acids and dipeptides
作者:S Wittmann
DOI:10.1016/s0968-0896(02)00044-5
日期:2002.6
Linking of siderophores to antibiotics improves the penetration and therefore increases the antibacterial activity of the antibiotics. We synthesized the acylated catecholates and hydroxamates as siderophore components for antibiotic conjugates to reduce side effects of unprotected catecholate and hydroxamate moieties. In this paper, we report on bis- and tris-catecholates and mixed catecholate hydroxamates based on diamino acids or dipeptides. These compounds were active as siderophores in a growth promotion assay under iron limitation. Most of the conjugates with beta-lactams showed high in vitro activity against Gram-negative bacteria especially Pseudomonas acruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia mareeseems and Stenotrophomonas maltophilia. The compounds with enhanced antibacterial activity use active iron uptake routes to penetrate the bacterial outer membrane barrier, demonstrated by assays with mutants deficient in components of the iron transport system. Correlation between chemical structure and biological activity was studied. (C) 2002 Published by Elsevier Science Ltd.
The Formation of Pyrroline and Tetrahydropyridine Rings in Amino Acids Catalyzed by Pyrrolysine Synthase (PylD)
The dehydrogenase PylDcatalyzes the ultimate step of the pyrrolysine pathway by converting the isopeptide L‐lysine‐Nε‐3R‐methyl‐D‐ornithine to the 22nd proteinogenic aminoacid. In this study, we demonstrate how PylD can be harnessed to oxidize various isopeptides to novel aminoacids by combining chemical synthesis with enzyme kinetics and X‐ray crystallography. The data enable a detailed description