Starch catabolism by a prominent human gut symbiont is directed by the recognition of amylose helices.

ABSTRACT: The human gut microbiota performs functions that are not encoded in our Homo sapiens genome, including the processing of otherwise undigestible dietary polysaccharides. Defining the structures of proteins involved in the import and degradation of specific glycans by saccharolytic bacteria complements genomic analysis of the nutrient-processing capabilities of gut communities. Here, we describe the atomic structure of one such protein, SusD, required for starch binding and utilization by Bacteroides thetaiotaomicron, a prominent adaptive forager of glycans in the distal human gut microbiota. The binding pocket of this unique alpha-helical protein contains an arc of aromatic residues that complements the natural helical structure of starch and imposes this conformation on bound maltoheptaose

SUBMITTER: Koropatkin NM 

PROVIDER: S-EPMC2563962 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature