The role of carbohydrate binding module cooperation in BaAmy7 hydrolysis of resistant starch

碳水化合物结合模块协同在BaAmy7抗性淀粉水解中的作用

• 批准号: 10329907
• 负责人: Amanda Lynn Photenhauer
• 金额: $ 3.87万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10329907
• 关键词: Acetates; Address; Affect; Amylases; Anti-Inflammatory Agents; Architecture; Bacteria; Bifidobacterium; Binding; Binding Proteins; Binding Sites; Biochemical; Butyrates; C-terminal; Carbohydrates; Catalytic Domain; Colon; Colorectal Cancer; Consumption; Cryoelectron Microscopy; Crystallization; Cytoplasmic Granules; Diet; Dietary Fiber; Digestion; Ecosystem; Enteral; Enzymes; Family; Feeds; Glucose; Glycoside Hydrolases; Glycosides; Goals; Growth; Health; Homeostasis; Human; Hydrolysis; Incidence; Individual; Knowledge; Length; Link; Measures; Mediating; Microbe; Modeling; Molecular; Molecular Conformation; Mutate; Nutrient; Organism; Outcome; Pancreas; Plants; Play; Potato; Probiotics; Production; Property; Proteins; Resistance; Role; Ruminococcus; Salivary; Side; Source; Starch; Structure; Supplementation; Testing; Time; Virus; Volatile Fatty Acids; Wheat; Work; X-Ray Crystallography; alpha-amylase; base; crystallinity; design; extracellular; gastrointestinal system; gut inflammation; gut microbiota; human microbiota; next generation; prebiotics; resistance mechanism; sugar; symbiont; tumorigenic

The gut microbiota plays a major role in colonic health and homeostasis. The growth of beneficial bacteria can be promoted by the administration of prebiotics in the human diet. Resistant starch is a prebiotic that preferentially promotes the growth of specialized bacteria, including Bifidobacterium adolescentis. Type 2 resistant starches are raw, granular starches that are inaccessible to most enzymes due to their tightly packed semi-crystalline structure. To break down and utilize resistant starch as a nutrient source, a bacterium must encode proteins that bind to the starch granule components and hydrolyze glycosidic linkages. Starch- specific carbohydrate binding modules (CBMs) are commonly appended to glycoside hydrolase family 13 (GH13) domains, which hydrolyze the glucose linkages in starch. B. adolescentis encodes seven extracellular GH13-containing enzymes including BaAmy7, which is highly active on raw potato and corn starch. BaAmy7 encodes four predicted CBMs, three of which belong to CBM families previously shown to bind raw starch. This proposal aims to understand the mechanism of action of BaAmy7 and how the coordinated effort of these four CBMs permits resistant starch as a substrate. I hypothesize that the binding and proper spatial arrangement of each of the four CBMs is required for maximal catalytic activity. To test this hypothesis, I will (1) dissect the role of individual CBMs in resistant starch hydrolysis by BaAmy7 and (2) elucidate the structural arrangement of BaAmy7 domains. Completion of these aims will lead to a better understanding of the molecular features that set apart BaAmy7 in its ability to hydrolyze resistant starch.

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