The Sus operon: a model system for starch uptake by the human gut Bacteroidetes.

Foley, Matthew H; Cockburn, Darrell W; Koropatkin, Nicole M

Foley, Matthew H; Cockburn, Darrell W; Koropatkin, Nicole M.

Afiliación

Foley MH; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Cockburn DW; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Koropatkin NM; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA. nkoropat@umich.edu.

Cell Mol Life Sci ; 73(14): 2603-17, 2016 07.

Article en En | MEDLINE | ID: mdl-27137179

RESUMEN

Resident bacteria in the densely populated human intestinal tract must efficiently compete for carbohydrate nutrition. The Bacteroidetes, a dominant bacterial phylum in the mammalian gut, encode a plethora of discrete polysaccharide utilization loci (PULs) that are selectively activated to facilitate glycan capture at the cell surface. The most well-studied PUL-encoded glycan-uptake system is the starch utilization system (Sus) of Bacteroides thetaiotaomicron. The Sus includes the requisite proteins for binding and degrading starch at the surface of the cell preceding oligosaccharide transport across the outer membrane for further depolymerization to glucose in the periplasm. All mammalian gut Bacteroidetes possess analogous Sus-like systems that target numerous diverse glycans. In this review, we discuss what is known about the eight Sus proteins of B. thetaiotaomicron that define the Sus-like paradigm of nutrient acquisition that is exclusive to the Gram-negative Bacteroidetes. We emphasize the well-characterized outer membrane proteins SusDEF and the α-amylase SusG, each of which have unique structural features that allow them to interact with starch on the cell surface. Despite the apparent redundancy in starch-binding sites among these proteins, each has a distinct role during starch catabolism. Additionally, we consider what is known about how these proteins dynamically interact and cooperate in the membrane and propose a model for the formation of the Sus outer membrane complex.

Asunto(s)

Bacteroidetes/metabolismo; Tracto Gastrointestinal/microbiología; Modelos Biológicos; Operón/genética; Almidón/metabolismo; Proteínas Bacterianas/química; Proteínas Bacterianas/metabolismo; Humanos

Palabras clave

Bacteroides thetaiotaomicron; Gut microbiota; Starch; Starch utilization system; Sus

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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Operón / Almidón / Tracto Gastrointestinal / Bacteroidetes / Modelos Biológicos Límite: Humans Idioma: En Revista: Cell Mol Life Sci Asunto de la revista: BIOLOGIA MOLECULAR Año: 2016 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Suiza

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