Origin of the 2-amino-2-deoxy-gluconate unit in Rhizobium leguminosarum lipid A. Expression cloning of the outer membrane oxidase LpxQ.

ABSTRACT: An unusual feature of the lipid A from the plant endosymbionts Rhizobium etli and Rhizobium leguminosarum is the presence of a proximal sugar unit consisting of a 2-amino-2-deoxy-gluconate moiety in place of glucosamine. An outer membrane oxidase that generates the 2-amino-2-deoxy-gluconate unit from a glucosamine-containing precursor is present in membranes of R. leguminosarum and R. etli but not in S. meliloti or Escherichia coli. We now report the identification of a hybrid cosmid that directs the overexpression of this activity by screening 1800 lysates of individual colonies of a R. leguminosarum 3841 genomic DNA library in the host strain R. etli CE3. Two cosmids (p1S11D and p1U12G) were identified in this manner and transferred into S. meliloti, in which they also directed the expre

SUBMITTER: Que-Gewirth NL 

PROVIDER: S-EPMC2548327 | biostudies-literature | 2003 Apr

REPOSITORIES: biostudies-literature