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

FEBS Lett. 2019 Mar;593(5):475-486. doi: 10.1002/1873-3468.13330. Epub 2019 Feb 7.


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 (ΔG° = +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 (Km ~ 12 μm), are competitively inhibited by menaquinone (Ki ~ 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'.

Keywords: bioenergetics; metabolism; mycobacteria; quinone; succinate dehydrogenase; tuberculosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Benzoquinones / metabolism*
  • Binding Sites
  • Electron Transport*
  • Hydrogen-Ion Concentration
  • Mycobacterium smegmatis / enzymology
  • Mycobacterium smegmatis / metabolism*
  • Oxidation-Reduction
  • Sequence Homology, Amino Acid
  • Succinate Dehydrogenase / antagonists & inhibitors
  • Succinate Dehydrogenase / chemistry
  • Succinate Dehydrogenase / metabolism*


  • Benzoquinones
  • quinone
  • Succinate Dehydrogenase