Alternate quinone coupling in a new class of succinate dehydrogenase may potentiate mycobacterial respiratory control

FEBS Letters

article

Kiel Hards¹  Salome Molano Rodriguez¹  Charlotte Cairns¹  Gregory M. Cook¹ 

[1] Department of Microbiology and Immunology, University of Otago;Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland

关键词: bioenergetics;    metabolism;    mycobacteria;    quinone;    succinate dehydrogenase;    tuberculosis;   

DOI  :  10.1002/1873-3468.13330

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 (DG° = +21 kJ·mol1 ). 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 (Km ~ 12 lM), are competitively inhibited by menaquinone (Ki ~ 25 lM) 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’.

【 授权许可】

Unknown