DOI: 10.1073/pnas.0606369104. The c i / b H moiety in the b 6 f complex studied by EPR: A pair of strongly interacting hemes

The c i / b H moiety in the b 6 f complex studied by EPR: A pair of strongly interacting hemes

10.1073/pnas.0606369104

Crossref journal-article

Proceedings of the National Academy of Sciences

Proceedings of the National Academy of Sciences (341)

Abstract

X-band EPR features in the region of 90–150 mT have previously been attributed to heme c i of the b 6 complex [Zhang H, Primak A, Bowman MK, Kramer DM, Cramer WA (2004) Biochemistry 43:16329–16336] and interpreted as arising from a high-spin species. However, the complexity of the observed spectrum is rather untypical for high-spin hemes. In this work, we show that addition of the inhibitor 2- n -nonyl-4-hydroxyquinoline N -oxide largely simplifies heme c i 's EPR properties. The spectrum in the presence of 2- n -nonyl-4-hydroxyquinoline N -oxide is demonstrated to be caused by a simple S = 5/2, rhombic species split by magnetic dipolar interaction ( A xx = 7.5 mT) with neighboring heme b H . The large spacing of lines in the uninhibited system, by contrast, cannot be rationalized solely on the basis of magnetic dipolar coupling but is likely to encompass strong contributions from exchange interactions. The role of the H 2 O/OH− molecule bridging heme c i 's Fe atom and heme b H 's propionate side chain in mediating these interactions is discussed.

Bibliography

Baymann, F., Giusti, F., Picot, D., & Nitschke, W. (2007). The c i / b H moiety in the b 6 f complex studied by EPR: A pair of strongly interacting hemes. Proceedings of the National Academy of Sciences, 104(2), 519â524.

Authors 4

Frauke Baymann (first)
Fabrice Giusti (additional)
Daniel Picot (additional)
Wolfgang Nitschke (additional)

References 15 Referenced 53

Dates

Type	When
Created	18 years, 7 months ago (Jan. 4, 2007, 1:30 a.m.)
Deposited	3 years, 4 months ago (April 12, 2022, 2:52 p.m.)
Indexed	2 days, 21 hours ago (Aug. 29, 2025, 6:25 a.m.)
Issued	18 years, 7 months ago (Jan. 9, 2007)
Published	18 years, 7 months ago (Jan. 9, 2007)
Published Online	18 years, 7 months ago (Jan. 9, 2007)
Published Print	18 years, 7 months ago (Jan. 9, 2007)

Funders 0

None

BibTeX

@article{Baymann_2007, title={The c i / b H moiety in the b 6 f complex studied by EPR: A pair of strongly interacting hemes}, volume={104}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.0606369104}, DOI={10.1073/pnas.0606369104}, number={2}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Baymann, Frauke and Giusti, Fabrice and Picot, Daniel and Nitschke, Wolfgang}, year={2007}, month=jan, pages={519–524} }

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