Mechanistic Insight into how β‐Ketoacyl ACP Synthase I (KasA) Recognizes the Fatty Acid Chain Length of its Substrate

• Published in: ChemPlusChem (Weinheim, Germany) Vol. 89; no. 7; pp. e202300568 - n/a
• Main Author: Lee, Wook
• Format: Journal Article
• Language: English
• Published: Germany 01.07.2024
• Subjects: 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase - chemistry; 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase - metabolism; allosterism; Beta-ketoacyl ACP synthase I (KasA); enzyme cooperativity; Fatty Acids - chemistry; Fatty Acids - metabolism; Isoenzymes; molecular dynamics; Molecular Dynamics Simulation; Mycobacterium tuberculosis - enzymology; Substrate Specificity; Thermodynamics; Beta-ketoacyl ACP synthase I (KasA); enzyme cooperativity; molecular dynamics; substrate specificity; allosterism
• DOI: 10.1002/cplu.202300568
• ISSN: 2192-6506

β‐ketoacyl ACP synthase I (KasA) has been considered as a promising drug target against Tuberculosis because it is known to play a pivotal role in the survival of Mycobacterium Tuberculosis, a causative agent of Tuberculosis. KasA catalyzes the reaction elongating only the acyl chain that is 16 carbon atoms in length or longer, but the molecular details of how KasA selectively recognizes only the substrate longer than a certain length still remain unknown. In the present study, this challenging subject is addressed, and to this end, molecular dynamics (MD) simulations and free energy calculations for actual substrate binding process are carried out. The results illustrate that the substrate specificity of KasA is highly linked to its cooperativity and this cooperativity is realized through the activation of catalytic residues. Through these results, the mechanistic details of how KasA can be selectively activated only by the substrate with a proper length are suggested. This study demonstrates the molecular details of how KasA can selectively elongate only the substrate longer than a certain length and reveals that this substrate specificity is closely associated with its cooperativity.