3CK7

B. thetaiotaomicron SusD with alpha-cyclodextrin

Summary for 3CK7

• Entry DOI: 10.2210/pdb3ck7/pdb
• Related: 3CK8 3CK9 3CKB 3CKC
• Related PRD ID: PRD_900015
• Descriptor: SusD, Cyclohexakis-(1-4)-(alpha-D-glucopyranose), CALCIUM ION, ... (4 entities in total)
• Functional Keywords: tpr repeat, carbohydrate binding, starch binding, sugar binding protein
• Biological source: Bacteroides thetaiotaomicron
• Total number of polymer chains: 4
• Total formula weight: 241275.39

Authors

Koropatkin, N.M.,Martens, E.C.,Gordon, J.I.,Smith, T.J. (deposition date: 2008-03-14, release date: 2008-04-01, Last modification date: 2023-08-30)

Primary citation

Koropatkin, N.M.,Martens, E.C.,Gordon, J.I.,Smith, T.J.
Starch catabolism by a prominent human gut symbiont is directed by the recognition of amylose helices.
Structure, 16:1105-1115, 2008

PubMed 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. Furthermore, SusD binds cyclic oligosaccharides with higher affinity than linear forms. The structures of several SusD/oligosaccharide complexes reveal an inherent ligand recognition plasticity dominated by the three-dimensional conformation of the oligosaccharides rather than specific interactions with the composite sugars.

PubMed: 18611383
DOI: 10.1016/j.str.2008.03.017

Experimental method

X-RAY DIFFRACTION (2.1 Å)