Structure of the cytochrome aa <subscript> 3 </subscript> -600 heme-copper menaquinol oxidase bound to inhibitor HQNO shows TM0 is part of the quinol binding site.
In: Proceedings of the National Academy of Sciences of the United States of America, Jg. 117 (2020-01-14), Heft 2, S. 872
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Zugriff:
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 aa 3 -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.
Competing Interests: The authors declare no competing interest.
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Structure of the cytochrome aa <subscript> 3 </subscript> -600 heme-copper menaquinol oxidase bound to inhibitor HQNO shows TM0 is part of the quinol binding site.
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Autor/in / Beteiligte Person: | Xu, J ; Ding, Z ; Liu, B ; Yi, SM ; Li, J ; Zhang, Z ; Liu, Y ; Liu, L ; Zhou, A ; Gennis, RB ; Zhu, J |
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Zeitschrift: | Proceedings of the National Academy of Sciences of the United States of America, Jg. 117 (2020-01-14), Heft 2, S. 872 |
Veröffentlichung: | Washington, DC : National Academy of Sciences, 2020 |
Medientyp: | academicJournal |
ISSN: | 1091-6490 (electronic) |
DOI: | 10.1073/pnas.1915013117 |
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