Premium
yciM is an essential gene required for regulation of lipopolysaccharide synthesis in E scherichia coli
Author(s) -
Mahalakshmi S.,
Sunayana M. R.,
SaiSree L.,
Reddy Manjula
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.12452
Subject(s) - bacterial outer membrane , lipid a , biology , lipopolysaccharide , mutant , escherichia coli , biochemistry , biosynthesis , microbiology and biotechnology , function (biology) , enzyme , gene , endocrinology
Summary The outer membrane of Gram‐negative bacteria is an asymmetric lipid bilayer consisting of an essential glycolipid lipopolysaccharide ( LPS ) in its outer leaflet and phospholipids in the inner leaflet. Here, we show that yciM , a gene encoding a tetratricopeptide repeat protein of unknown function, modulates LPS levels by negatively regulating the biosynthesis of lipid A , an essential constituent of LPS . Inactivation of yciM resulted in high LPS levels and cell death in E scherichia coli ; recessive mutations in lpxA , lpxC or lpxD that lower the synthesis of lipid A , or a gain of function mutation in fabZ that increases the formation of membrane phospholipids, alleviated the yciM mutant phenotypes. A modest increase in YciM led to significant reduction of LPS and increased sensitivity to hydrophobic antibiotics. YciM was shown to regulate LPS by altering LpxC , an enzyme that catalyses the first committed step of lipid A biosynthesis. Regulation of LpxC by YciM was contingent on the presence of FtsH , an essential membrane‐anchored protease known to degrade LpxC , suggesting that FtsH and YciM act in concert to regulate synthesis of lipid A . In summary, this study demonstrates an essential role for YciM in regulation of LPS biosynthesis in E . coli .