- Ten-membered rings as key interaction motifs in folding of desmuramyl di-, tri-, and tetrapeptides
-
Muropeptides are fragments of polymeric peptidoglycan, unique constituent of bacterial cell walls, acting as immunostimulators (adjuvants). The smallest biologically active unit of peptidoglycan is N-acetylmuramyl-L-alanyl-D-isoglutamine. In this paper, the synthesis and conformational analysis of desmuramyl peptides, derivatives lacking the N-acetylmuramyl moiety, is described. Systematic conformational analysis (bottom-up approach) of peptides in zwitterionic and non-zwitterionic forms of corresponding desmuramyl di-, tri-, and tetrapeptides was performed and results were compared with experimental data obtained by NMR study. Ten-membered ring (C10, N1bH?O3) formed between isoGln amide group and C=O of AdGly was found to be a key interaction that constitutes the central structural spine and initiates β-turn-like folding in our model peptide systems.
- Ribi?, Rosana,Kodrin, Ivan,Biljan, Ivana,Paurevi?, Marija,Tomi?, Sr?anka
-
-
Read Online
- Functional characterization of the n-acetylmuramyl-l-alanine amidase, ami1, from Mycobacterium abscessus
-
Peptidoglycan (PG) is made of a polymer of disaccharides organized as a three-dimensional mesh-like network connected together by peptidic cross-links. PG is a dynamic structure that is essential for resistance to environmental stressors. Remodeling of PG occurs throughout the bacterial life cycle, particularly during bacterial division and separation into daughter cells. Numerous autolysins with various substrate specificities participate in PG remodeling. Expression of these enzymes must be tightly regulated, as an excess of hydrolytic activity can be detrimental for the bacteria. In non-tuberculous mycobacteria such as Mycobacterium abscessus, the function of PG-modifying enzymes has been poorly investigated. In this study, we characterized the function of the PG amidase, Ami1 from M. abscessus. An ami1 deletion mutant was generated and the phenotypes of the mutant were evaluated with respect to susceptibility to antibiotics and virulence in human macrophages and zebrafish. The capacity of purified Ami1 to hydrolyze muramyl-dipeptide was demonstrated in vitro. In addition, the screening of a 9200 compounds library led to the selection of three compounds inhibiting Ami1 in vitro. We also report the structural characterization of Ami1 which, combined with in silico docking studies, allows us to propose a mode of action for these inhibitors.
- Küssau, Tanja,Van Wyk, Ni?l,Johansen, Matt D.,Alsarraf, Husam M. A. B.,Neyret, Aymeric,Hamela, Claire,S?rensen, Kasper K.,Thygesen, Mikkel B.,Beauvineau, Claire,Kremer, Laurent,Blaise, Micka?l
-
-
- SYNTHESIS OF PEPTIDES, GLYCO DERIVATIVES AND GLYCOPEPTIDES FROM BACTERIAL CELL WALLS
-
Synthesis in solution and in solid phase was used to prepare alanyl-D-isoglutamine (VI), alanyl-D-isoglutaminyl-Nε-p-toluenesulfonyl-lysyl-D-alanine methyl ester (XIII), alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanine methyl ester (XIV), alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanyl-pentaglycine methyl ester and amide (XXXI, XXXII), methyl ester (XXXV), methyl ester (XXXVII), N-acetylmuramyl-alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanyl-pentaglycine amide (XXXIX), methyl ester (XLI), and methyl ester (XLIII).Thetetrapeptides, nonapeptides, and tridecapeptides show a pronounced pyrogenic effect.Imunoadjuvant activity was observed not only with the glycopeptides but also with nonapeptide XXXI.
- Zaoral, Milan,Jezek, Jan,Krchnak, Viktor,Straka, Radovan
-
p. 1424 - 1446
(2007/10/02)
-