%0 Journal Article
%T Unusual 1-3 peptidoglycan cross-links in Acetobacteraceae are made by L,D-transpeptidases with a catalytic domain distantly related to YkuD domains.
%A Alamán-Zárate MG
%A Rady BJ
%A Evans CA
%A Pian B
%A Greetham D
%A Marecos-Ortiz S
%A Dickman MJ
%A Lidbury IDEA
%A Lovering AL
%A Barstow BM
%A Mesnage S
%J J Biol Chem
%V 300
%N 1
%D 2024 Jan 23
%M 38006948
暂无%R 10.1016/j.jbc.2023.105494
%X Peptidoglycan is an essential component of the bacterial cell envelope that contains glycan chains substituted by short peptide stems. Peptide stems are polymerized by D,D-transpeptidases, which make bonds between the amino acid in position four of a donor stem and the third residue of an acceptor stem (4-3 cross-links). Some bacterial peptidoglycans also contain 3-3 cross-links that are formed by another class of enzymes called L,D-transpeptidases which contain a YkuD catalytic domain. In this work, we investigate the formation of unusual bacterial 1-3 peptidoglycan cross-links. We describe a version of the PGFinder software that can identify 1-3 cross-links and report the high-resolution peptidoglycan structure of Gluconobacter oxydans (a model organism within the Acetobacteraceae family). We reveal that G. oxydans peptidoglycan contains peptide stems made of a single alanine as well as several dipeptide stems with unusual amino acids at their C-terminus. Using a bioinformatics approach, we identified a G. oxydans mutant from a transposon library with a drastic reduction in 1-3 cross-links. Through complementation experiments in G. oxydans and recombinant protein production in a heterologous host, we identify an L,D-transpeptidase enzyme with a domain distantly related to the YkuD domain responsible for these non-canonical reactions. This work revisits the enzymatic capabilities of L,D-transpeptidases, a versatile family of enzymes that play a key role in bacterial peptidoglycan remodelling.