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

基本信息

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
项目类别：
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

项目摘要

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.

肠道微生物群在结肠健康和体内平衡中发挥着重要作用。有益细菌的生长可以通过在人类饮食中添加益生元来促进。抗性淀粉是一种益生元，优先促进特殊细菌的生长，包括青春双歧杆菌。 2型抗性淀粉是原始的颗粒淀粉，由于其紧密包装，大多数酶无法接触到半结晶结构。为了分解并利用抗性淀粉作为营养源，细菌必须编码与淀粉颗粒成分结合并水解糖苷键的蛋白质。淀粉- 特定的碳水化合物结合模块 (CBM) 通常附加到糖苷水解酶家族 13 (GH13) 结构域，水解淀粉中的葡萄糖键。青春双歧杆菌编码七种细胞外含有 GH13 的酶，包括 BaAmy7，它对生马铃薯和玉米淀粉具有高度活性。巴艾米7 编码四种预测的 CBM，其中三种属于先前显示可结合生淀粉的 CBM 家族。这该提案旨在了解 BaAmy7 的作用机制以及这四个因素如何协调作用 CBM 允许抗性淀粉作为底物。我假设绑定和适当的空间安排四种 CBM 中的每一种都需要最大催化活性。为了检验这个假设，我将（1）剖析这个角色 BaAmy7 在抗性淀粉水解中对单个 CBM 的影响，以及 (2) 阐明了其结构排列 BaAmy7 域。完成这些目标将有助于更好地理解分子特征 BaAmy7 因其水解抗性淀粉的能力而与众不同。