Enzyme Multifunctionality by Control of Substrate Positioning Within the Catalytic Cycle—A QM/MM Study of Clavaminic Acid Synthase. Issue 6 (29th December 2020)

• Record Type: Journal Article
• Authors: Wojdyla, Zuzanna; Borowski, Tomasz
• Is Part Of: Chemistry. Volume 27:Issue 6(2021)
• Page Start: 2196
• Page End: 2211
• Publication Date: 2020-12-29
• Subjects: C−H activation -- dehydrogenation -- enzyme catalysis -- hydroxylation -- metalloenzymes -- reaction mechanisms; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202004426
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Clavaminic acid synthase from Streptomyces clavuligerus is an Fe II /2‐oxoglutarate‐dependent dioxygenase, crucial for the biosynthesis of the β‐lactamase inhibitor clavulanic acid. It catalyses three consecutive oxidative reactions, that is, hydroxylation, cyclisation and desaturation, in a single binding cavity. As follows from the results of this QM/MM study, CAS versatility and selectivity depends on the binding cavity, which interplays differently with the substrate for each reaction. The enzyme–substrate interactions affect the substrate's ability to re‐position during the reaction, either constraining it in its primary position, which impedes processes other than oxygen rebound, or allowing change, which facilitates desaturation. This differential effect originates from two aspartate residues, which strongly interact with the guanidine group of the hydroxylation substrate and stabilise the orientation of the molecule. These residues interact less effectively with the smaller amine group of the desaturation substrate(s), aiding their re‐positioning and the subsequent formation of a double bond. Abstract : Enzyme control . A QM/MM study of clavaminic acid synthase reveals that the enzyme–substrate interactions either constrain the position of the substrate during reaction, hindering processes other than OH rebound, or allow some change in the substrate's position/conformation, thus leading to desaturation. This differential effect originates from the different strengths of the interactions between two aspartate residues and the hydroxylation/desaturation substrates.