Details

Autor(en) / Beteiligte

• Xu, Jingjing
• Ding, Ziqiao
• Liu, Bing
• Yi, Sophia M.
• Li, Jiao
• Zhang, Zhengguang
• Liu, Yuchen
• Li, Jin
• Liu, Liu
• Zhou, Aiwu
• Gennis, Robert B.
• Zhu, Jiapeng

Titel

Structure of the cytochrome aa 3 -600 heme-copper menaquinol oxidase bound to inhibitor HQNO shows TM0 is part of the quinol binding site

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2019-12, Vol.117 (2)

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2019

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Virtually all proton-pumping terminal respiratory oxygen reductases are members of the heme-copper oxidoreductase superfamily. Most of these enzymes use reduced cytochrome c 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 c oxidases. The current work reports the 3.6-Å-resolution X-ray structure of the cytochrome aa3-600 menaquinol oxidase from Bacillus subtilis 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 (N-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.