Rapid Electron Transfer within the III-IV Supercomplex in Corynebacterium glutamicum

Graf, Simone Sandra; Fedotovskaya, Olga; Kao, Wei-Chun; Hunte, Carola; Ädelroth, Pia; Bott, Michael; von Ballmoos, Christoph; Brzezinski, Peter (2016). Rapid Electron Transfer within the III-IV Supercomplex in Corynebacterium glutamicum. Scientific Reports, 6(1) Nature Publishing Group 10.1038/srep34098

[img]
Preview
Text
srep34098.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (1MB) | Preview

Complex III in C. glutamicum has an unusual di-heme cyt. c1 and it co-purifies with complex IV in a supercomplex. Here, we investigated the kinetics of electron transfer within the supercomplex and in the cyt. aa3 alone (cyt. bc1 was removed genetically). In the reaction of the reduced cyt. aa3 with O2, we identified the same sequence of events as with other A-type oxidases. However, even though this reaction is associated with proton uptake, no pH dependence was observed in the kinetics. For the cyt. bc1-cyt. aa3 supercomplex, we observed that electrons from the c-hemes were transferred to CuA with time constants 0.1-1 ms. The b-hemes were oxidized with a time constant of 6.5 ms, indicating that this electron transfer is rate-limiting for the overall quinol oxidation/O2 reduction activity (~210 e-/s). Furthermore, electron transfer from externally added cyt. c to cyt. aa3 was significantly faster upon removal of cyt. bc1 from the supercomplex, suggesting that one of the c-hemes occupies a position near CuA. In conclusion, isolation of the III-IV-supercomplex allowed us to investigate the kinetics of electron transfer from the b hemes, via the di-heme cyt. c1 and heme a to the heme a3-CuB catalytic site of cyt. aa3.

Item Type:

Journal Article (Original Article)

Creator:

Graf, Simone Sandra

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Graf, Simone Sandra and von Ballmoos, Christoph

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

2045-2322

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Simone Graf

Date Deposited:

27 Jul 2017 08:35

Last Modified:

30 Jul 2017 02:16

Publisher DOI:

10.1038/srep34098

BORIS DOI:

10.7892/boris.101357

URI:

https://boris.unibe.ch/id/eprint/101357

Actions (login required)

Edit item Edit item
Provide Feedback