The structure of a Lactobacillus helveticus chlorogenic acid esterase and the dynamics of its insertion domain provide insights into substrate binding

• Published in: FEBS letters Vol. 597; no. 23; pp. 2946 - 2962
• Main Authors: Omori, Kellie K., Drucker, Charles T., Okumura, Tracie L. S., Carl, Nathaniel B., Dinn, Brianna T., Ly, Destiny, Sacapano, Kylie N., Tajii, Allie, Owens, Cedric P.
• Format: Journal Article
• Language: English
• Published: England 01.12.2023
• Subjects: Bacteria - metabolism; Carboxylic Ester Hydrolases - chemistry; chlorogenic acid; Chlorogenic Acid - metabolism; chlorogenic acid esterase; ferulic acid esterase; hydrolase; Lactobacillus helveticus - genetics; Lactobacillus helveticus - metabolism; substrate specificity; ferulic acid esterase; chlorogenic acid; hydrolase; chlorogenic acid esterase; substrate specificity
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.14731

Chlorogenic acid esterases (ChlEs) are a useful class of enzymes that hydrolyze chlorogenic acid (CGA) into caffeic and quinic acids. ChlEs can break down CGA in foods to improve their sensory properties and release caffeic acid in the digestive system to improve the absorption of bioactive compounds. This work presents the structure, molecular dynamics, and biochemical characterization of a ChlE from Lactobacillus helveticus (Lh). Molecular dynamics simulations suggest that substrate access to the active site of LhChlE is modulated by two hairpin loops above the active site. Docking simulations and mutational analysis suggest that two residues within the loops, Gln145 and Lys164, are important for CGA binding. Lys164 provides a slight substrate preference for CGA, whereas Gln145 is required for efficient turnover. This work is the first to examine the dynamics of a bacterial ChlE and provides insights on substrate binding preference and turnover in this type of enzyme. Chlorogenic acid esterases are biotechnologically useful enzymes that hydrolyze unwanted chlorogenic acid in foods, thereby improving their sensory properties. This work determines how two residues on hairpin loops above the active site influence substrate binding and turnover in a bacterial chlorogenic acid esterase.