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

> **NIH NIH F31** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2022 · $38,665

## Abstract

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.

## Key facts

- **NIH application ID:** 10329907
- **Project number:** 5F31AT011282-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Amanda Lynn Erpenbeck
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $38,665
- **Award type:** 5
- **Project period:** 2021-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10329907

## Citation

> US National Institutes of Health, RePORTER application 10329907, The role of carbohydrate binding module cooperation in BaAmy7 hydrolysis of resistant starch (5F31AT011282-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10329907. Licensed CC0.

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