Expression cloning of three Rhizobium leguminosarum lipopolysaccharide core galacturonosyltransferases.

ABSTRACT: The lipid A and core regions of the lipopolysaccharide in Rhizobium leguminosarum, a nitrogen-fixing plant endosymbiont, are strikingly different from those of Escherichia coli. In R. leguminosarum lipopolysaccharide, the inner core is modified with three galacturonic acid (GalA) moieties, two on the distal 3-deoxy-D-manno-octulosonic acid (Kdo) unit and one on the mannose residue. Here we describe the expression cloning of three novel GalA transferases from a 22-kb R. leguminosarum genomic DNA insert-containing cosmid (pSGAT). Two of these enzymes modify the substrate, Kdo2-[4'-(32)P]lipid IV(A) and its 1-dephosphorylated derivative on the distal Kdo residue, as indicated by mild acid hydrolysis. The third enzyme modifies the mannose unit of the substrate mannosyl-Kdo2-1-dephospho-[4'-(32

SUBMITTER: Kanjilal-Kolar S 

PROVIDER: S-EPMC2814240 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature