Dynamics of the K B Proton Pathway in Cytochrome ba 3 from Thermus thermophilus

The ba 3 cytochrome c oxidase from Thermus thermophilus is a B‐type oxygen‐reducing heme‐copper oxidase and a proton pump. It uses only one proton pathway for transfer of protons to the catalytic site, the K B pathway. It was previously shown that the ba 3 oxidase has an overall similar reaction seq...

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Bibliographic Details
Published in:Israel journal of chemistry 2017-05, Vol.57 (5), p.424-436
Main Authors: von Ballmoos, Christoph, Smirnova, Irina, Poiana, Federica, Gonska, Nathalie, Chang, Hsin‐Yang, Gennis, Robert B., Brzezinski, Peter, Ädelroth, Pia
Format: Article
Language:English
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Summary:The ba 3 cytochrome c oxidase from Thermus thermophilus is a B‐type oxygen‐reducing heme‐copper oxidase and a proton pump. It uses only one proton pathway for transfer of protons to the catalytic site, the K B pathway. It was previously shown that the ba 3 oxidase has an overall similar reaction sequence to that in mitochondrial‐like A‐type oxidases. However, the timing of loading the pump site, and formation and decay of catalytic intermediates is different in the two types of oxidases. In the present study, we have investigated variants in which two amino acids of the K B proton pathway leading to the catalytic site were exchanged; Tyr‐248 (located ∼23 Å below the active site towards the cytoplasm) in subunit I (Y248T) and Glu‐15 (∼26 Å below the active site, ∼16 Å from Tyr‐248) in subunit II (E15 II Q). Even though the overall catalytic turnover in these two variants is similar and very low (
ISSN:0021-2148
1869-5868
DOI:10.1002/ijch.201600136