Identification and characterization of an Azotobacter vinelandii type I secretion system responsible for export of the AlgE-type mannuronan C-5-epimerases.

ABSTRACT: Alginate is a linear copolymer of beta-d-mannuronic acid and its C-5-epimer, alpha-l-guluronic acid. During biosynthesis, the polymer is first made as mannuronan, and various fractions of the monomers are then epimerized to guluronic acid by mannuronan C-5-epimerases. The Azotobacter vinelandii genome encodes a family of seven extracellular such epimerases (AlgE1 to AlgE7) which display motifs characteristic for proteins secreted via a type I pathway. Putative ATPase-binding cassette regions from the genome draft sequence of the A. vinelandii OP strain and experimentally verified type I transporters from other species were compared. This analysis led to the identification of one putative A. vinelandii type I system (eexDEF). The corresponding genes were individually disrupted in A. vinelan

SUBMITTER: Gimmestad M 

PROVIDER: S-EPMC1540039 | biostudies-literature | 2006 Aug

REPOSITORIES: biostudies-literature