Distinct Adjacent Substrate Binding Pocket Regulates the Activity of a Decameric Feruloyl Esterase from Bacteroides thetaiotaomicron

• DOI: 10.1021/acs.jafc.4c06286
• Publication Date: 2024-10-07T04:46:11Z
• Authors: Yulu Wang; Guoming Du; Yuebin Zhang; Haiyan Yu; Shujun Liu; Zhaoxing Wang; Xiaochen Ma; Xue Wei; Boting Wen; Zhen Li; Shilong Fan; Fengjiao Xin
• Keywords: Bacteroides thetaiotaomicron; Esterase

Understanding how the human gut microbiota contribute to metabolism of dietary carbohydrates is great interest, particularly those with ferulic acid (FA) decorations that have manifold health benefits. Here, we report crystal structure a decameric feruloyl esterase (BtFae) from Bacteroides thetaiotaomicron in complex methyl ferulate (MFA), revealing MFA situated noncatalytic substrate binding pocket adjacent catalytic pocket. Molecular docking and mutagenesis studies further demonstrated affects active site negatively regulates BtFae activity on both synthetic natural xylan substrates. Additionally, quantum mechanics (QM) calculations were employed investigate process product release, identified TS_2 acylation step rate-limiting. Collectively, this study unmasks novel regulatory mechanism FAE activity, which may investigation FA-conjugated polysaccharides gut.