The composition of the Bacillus subtilis aerobic respiratory chain supercomplexes.
Bacillus subtilis has a bifurcated respiratory chain composed of a cytochrome branch and a quinol oxidase branch. The respiratory complexes of this bacterium have been elucidated mostly by the analysis of the genome and by the isolation of individual complexes. The supramolecular organization of this respiratory chain is not known. In this work, we have analyzed the organization of the supercomplex in membranes isolated from B. subtilis grown in aerobic conditions in a medium with 3 % succinate. We used two different native electrophoretic techniques, clear native electrophoresis (CNE) and blue native electrophoresis (BNE). Using a heme-specific stain and Coomassie blue stain with in-gel activity assays followed by mass spectrometry, we identified the proteins resolved in both the first and second dimensions of the electrophoreses to detect the supercomplexes. We found that complexes b                         (                            6                         )                         c and caa                         (                            3                         ) form a very high molecular mass supercomplex with the membrane-bound cytochrome c                         (                            550                         ) and with ATP synthase. Most of the ATP synthase was found as a monomer. Succinate dehydrogenase was identified within a high molecular band between F(0)F(1) and F(1) and together with nitrate reductase. The type-2 NADH dehydrogenase was detected within a low molecular mass band. Finally, the quinol oxidase aa                         (                            3                         ) seems to migrate as an oligomer of high molecular mass.
F.E.S. Iztacala UBIMED, Universidad Nacional Autónoma de México, Avenida de los Barrios #1. Los Reyes Iztacala, Tlalnepantla, Edo. de México, Mexico, 54090.
Led Yered Jafet
LY
García Montes de Oca
Alicia
A
Chagolla-López
Luis
L
González de la Vara
Tecilli
T
Cabellos-Avelar
Carlos
C
Gómez-Lojero
Emma Berta
EB
Gutiérrez Cirlos
D000332:Aerobiosis / Q000502:physiology; D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D003580:Cytochromes / Q000737:chemistry* / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D003580:Cytochromes; D009097:Multienzyme Complexes