A two-component Kdo hydrolase in the inner membrane of Francisella novicida.

ABSTRACT: Lipid A coats the outer surface of the outer membrane of Gram-negative bacteria. In Francisella tularensis subspecies novicida lipid A is present either as the covalently attached anchor of lipopolysaccharide (LPS) or as free lipid A. The lipid A moiety of Francisella LPS is linked to the core domain by a single 2-keto-3-deoxy-D-manno-octulosonic acid (Kdo) residue. F. novicida KdtA is bi-functional, but F. novicida contains a membrane-bound Kdo hydrolase that removes the outer Kdo unit. The hydrolase consists of two proteins (KdoH1 and KdoH2), which are expressed from adjacent, co-transcribed genes. KdoH1 (related to sialidases) has a single predicted N-terminal transmembrane segment. KdoH2 contains 7 putative transmembrane sequences. Neither protein alone catalyses Kdo cleavage when expr

SUBMITTER: Zhao J 

PROVIDER: S-EPMC2978271 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature