Structure, kinetics, and mechanism of Pseudomonas putida sulfoquinovose dehydrogenase, the first enzyme in the sulfoglycolytic Entner-Doudoroff pathway

Burchill, L; Sharma, M; Soler, NM; Goddard-Borger, ED; Davies, GJ; Williams, SJ

Author(s): Burchill, L; Sharma, M; Soler, NM; Goddard-Borger, ED; Davies, GJ; Williams, SJ;
Details: Publication Year 2025-01-22,Volume 482,Issue #2,Page 57-72
Journal Title: Biochemical Journal
Abstract: The sulfosugar sulfoquinovose (SQ) is catabolized through the sulfoglycolytic Entner-Doudoroff pathway, beginning with the oxidation of SQ to sulfogluconolactone by SQ dehydrogenase. We present a comprehensive structural and kinetic characterization of Pseudomonas putida SQ dehydrogenase (PpSQDH). PpSQDH is a tetrameric enzyme belonging to the short-chain dehydrogenase/reductase (SDR) superfamily with a strong preference for NAD+ over NADP+. Kinetic analysis revealed a rapid equilibrium ordered mechanism in which the NAD+ cofactor is the first substrate to bind, and NADH is the last product to dissociate. Structural studies revealed a homotetrameric structure in solution and crystals, involving cross-subunit interactions in which the C-terminus residue (Gln260) inserts into the diagonally opposite subunit to form part of the second shell of residues lining the active site. Complexes of PpSQDH with SQ or NAD+ provide insight into the recognition of SQ and together with the kinetic analysis allow the proposal of a catalytic reaction mechanism. Our findings illuminate the mechanism of SQ degradation and the evolution of the SDR superfamily for organosulfonate catabolism.
Publisher: Portland Press
Keywords: *Pseudomonas putida/enzymology/genetics; Kinetics; *NAD/metabolism; *Bacterial Proteins/metabolism/chemistry/genetics; Crystallography, X-Ray; Substrate Specificity; Catalytic Domain; Carbohydrate Dehydrogenases/metabolism/chemistry/genetics; NADP/metabolism; Models, Molecular; Methylglucosides; enzyme mechanism; organosulfur; short-chain dehydrogenase/reductase; sulfoglycolysis; sulfur cycle
Research Division(s): New Medicines and Diagnostics
PubMed ID: 39840830
Publisher's Version: https://doi.org/10.1042/bcj20240605
Open Access at Publisher's Site: https://doi.org/10.1042/BCJ20240605
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2025-02-07 02:57:12

Last Modified: 2025-02-07 03:13:23