Alternate quinone coupling in a new class of succinate dehydrogenase may potentiate mycobacterial respiratory control. Issue 5 (7th February 2019)

• Record Type: Journal Article
• Authors: Hards, Kiel; Rodriguez, Salome Molano; Cairns, Charlotte; Cook, Gregory M.
• Is Part Of: FEBS letters. Volume 593:Issue 5(2019)
• Page Start: 475
• Page End: 486
• Publication Date: 2019-02-07
• Subjects: bioenergetics -- metabolism -- mycobacteria -- quinone -- succinate dehydrogenase -- tuberculosis; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1002/1873-3468.13330
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : There is a paucity of information on the unique components that pathogens use to form respiratory chains. It is not known why mycobacteria encode multiple succinate dehydrogenases (SDHs) to perform menaquinone‐linked succinate oxidation, a thermodynamically unfavorable reaction (Δ G ° = +21 kJ·mol −1 ). In other bacteria, specific di‐heme SDHs overcome this using the proton motive force. It is unknown if this holds true in mycobacteria. Here, succinate dehydrogenase 1 (Sdh1) from Mycobacterium smegmatis was purified and found to not contain heme cofactors. Proteoliposomes, containing Sdh1, are active with coenzyme Q2 ( K m ~ 12 μm ), are competitively inhibited by menaquinone ( K i ~ 25 μm ) and do not generate or consume electrochemical gradients. Sdh1 may use higher potential quinones in vivo and forms a novel SDH class, which we term 'Type F'. Abstract :