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Identification of a broad family of lipid A late acyltransferases with non‐canonical substrate specificity
Author(s) -
Rubin Erica J.,
O'Brien John P.,
Ivanov Petko L.,
Brodbelt Jennifer S.,
Trent M. Stephen
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12501
Subject(s) - acyltransferases , acyltransferase , biology , biochemistry , lipid a , enzyme , transferase , acyl carrier protein , biosynthesis , escherichia coli , bacteria , gene , genetics
Summary Most Gram‐negative organisms produce lipopolysaccharide ( LPS ), a complex macromolecule anchored to the bacterial membrane by the lipid A moiety. Lipid A is synthesized via the R aetz pathway, a conserved nine‐step enzymatic process first characterized in E scherichia coli . The E psilonproteobacterium H elicobacter pylori uses the R aetz pathway to synthesize lipid A ; however, only eight of nine enzymes in the pathway have been identified in this organism. Here, we identify the missing acyltransferase, Jhp 0255, which transfers a secondary acyl chain to the 3′‐linked primary acyl chain of lipid A , an activity similar to that of E . coli LpxM . This enzyme, reannotated as LpxJ due to limited sequence similarity with LpxM , catalyses addition of a C 12:0 or C 14:0 acyl chain to the 3′‐linked primary acyl chain of lipid A , complementing an E . coli LpxM mutant. Enzymatic assays demonstrate that LpxJ and homologues in C ampylobacter jejuni and W olinella succinogenes can act before the 2′ secondary acyltransferase, LpxL , as well as the 3‐deoxy‐ d ‐ manno ‐octulosonic acid ( K do) transferase, KdtA . Ultimately, LpxJ is one member of a large class of acyltransferases found in a diverse range of organisms that lack an E . coli LpxM homologue, suggesting that LpxJ participates in lipid A biosynthesis in place of an LpxM homologue.