6KOB

X-ray Structure of the proton-pumping cytochrome aa3-600 menaquinol oxidase from Bacillus subtilis

Summary for 6KOB

• Entry DOI: 10.2210/pdb6kob/pdb
• Descriptor: AA3-600 quinol oxidase subunit I, Quinol oxidase subunit 2, AA3-600 quinol oxidase subunit IIII, ... (7 entities in total)
• Functional Keywords: menaquinol oxidase, complex, proton pumping, oxidoreductase
• Biological source: Bacillus subtilis; More
• Total number of polymer chains: 8
• Total formula weight: 291647.51

Authors

Xu, J.,Ding, Z.,Liu, B.,Li, J.,Gennis, R.B.,Zhu, J. (deposition date: 2019-08-09, release date: 2020-01-15, Last modification date: 2024-03-27)

Primary citation

Xu, J.,Ding, Z.,Liu, B.,Yi, S.M.,Li, J.,Zhang, Z.,Liu, Y.,Li, J.,Liu, L.,Zhou, A.,Gennis, R.B.,Zhu, J.
Structure of the cytochromeaa3-600 heme-copper menaquinol oxidase bound to inhibitor HQNO shows TM0 is part of the quinol binding site.
Proc.Natl.Acad.Sci.USA, 117:872-876, 2020

PubMed Abstract: Virtually all proton-pumping terminal respiratory oxygen reductases are members of the heme-copper oxidoreductase superfamily. Most of these enzymes use reduced cytochrome as a source of electrons, but a group of enzymes have evolved to directly oxidize membrane-bound quinols, usually menaquinol or ubiquinol. All of the quinol oxidases have an additional transmembrane helix (TM0) in subunit I that is not present in the related cytochrome oxidases. The current work reports the 3.6-Å-resolution X-ray structure of the cytochrome -600 menaquinol oxidase from containing 1 equivalent of menaquinone. The structure shows that TM0 forms part of a cleft to accommodate the menaquinol-7 substrate. Crystals which have been soaked with the quinol-analog inhibitor HQNO (-oxo-2-heptyl-4-hydroxyquinoline) or 3-iodo-HQNO reveal a single binding site where the inhibitor forms hydrogen bonds to amino acid residues shown previously by spectroscopic methods to interact with the semiquinone state of menaquinone, a catalytic intermediate.

PubMed: 31888984
DOI: 10.1073/pnas.1915013117

Experimental method

X-RAY DIFFRACTION (3.6 Å)