Proton Environment of Reduced Rieske Iron-Sulfur Cluster Probed by Two-Dimensional ESEEM Spectroscopy | Sciact - CRIS-system of Boreskov Institute of Catalysis

Proton Environment of Reduced Rieske Iron-Sulfur Cluster Probed by Two-Dimensional ESEEM Spectroscopy Full article

Journal

The Journal of Physical Chemistry A
ISSN: 1089-5639 , E-ISSN: 1520-5215

Output data

Year: 2009, Volume: 113, Number: 4, Pages: 653-667 Pages count : 15 DOI: 10.1021/jp806789x

Tags

CYTOCHROME BC(1) COMPLEX; ECHO ENVELOPE MODULATION; SPIN POPULATION-DISTRIBUTION; COUPLED ELECTRON-TRANSFER; NUCLEAR DOUBLE-RESONANCE; ENERGY-CONVERSION SITEH-1 ENDOR SPECTROSCOPY; Fe-S PROTEIN; 2Fe-2S CLUSTER; Q(O) SITE

Authors

Kolling Derrick R.J. ¹ , Samoilova Rimma I. ^1,2 , Shubin Alexander A. ³ , Crofts Antony R. ^1,4 , Dikanov Sergei A. ⁵

Affiliations

1	Center for Biophysics and Computational Biology, University of Illinois, Urbana, Illinois 61801
2	Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
3	Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk 6300090, Russia
4	Department of Biochemistry, University of Illinois, Urbana, Illinois 61801
5	Department of Veterinary Clinical Medicine, University of Illinois, Urbana, Illinois 61801

Funding (4)

1	National Institutes of Health	GM 35438
2	National Institutes of Health	GM 62954
3	National Institutes of Health	S10-RR15878
4	John E. Fogarty Foundation	PHS 1 R03 TW 01495

The proton environment of the reduced [2Fe-2S] cluster in the water-soluble head domain of the Rieske iron-sulfur protein (ISF) from the cytochrome bc1 complex of Rhodobacter sphaeroides has been studied by orientation-selected X-band 2D ESEEM. The 2D spectra show multiple cross-peaks from protons, with considerable overlap. Samples in which 1 H2O water was replaced by 2H2O were used to determine which of the observed peaks belong to exchangeable protons, likely involved in hydrogen bonds in the neighborhood of the cluster. By correlating the cross-peaks from 2D spectra recorded at different parts of the EPR spectrum, lines from nine distinct proton signals were identified. Assignment of the proton signals was based on a point-dipole model for interaction with electrons of Fe(III) and Fe(II) ions, using the high-resolution structure of ISF from Rb. sphaeroides. Analysis of experimental and calculated tensors has led us to conclude that even 2D spectra do not completely resolve all contributions from nearby protons. Particularly, the seven resolved signals from nonexchangeable protons could be produced by at least 13 protons. The contributions from exchangeable protons were resolved by difference spectra (1H2O minus 2H2O), and assigned to two groups of protons with distinct anisotropic hyperfine values. The largest measured coupling exceeded any calculated value. This discrepancy could result from limitations of the point dipole approximation in dealing with the distribution of spin density over the sulfur atoms of the cluster and the cysteine ligands, or from differences between the structure in solution and the crystallographic structure. The approach demonstrated here provides a paradigm for a wide range of studies in which hydrogen-bonding interactions with metallic centers has a crucial role in understanding the function.

Kolling D.R.J. , Samoilova R.I. , Shubin A.A. , Crofts A.R. , Dikanov S.A.
Proton Environment of Reduced Rieske Iron-Sulfur Cluster Probed by Two-Dimensional ESEEM Spectroscopy

The Journal of Physical Chemistry A. 2009. V.113. N4. P.653-667. DOI: 10.1021/jp806789x WOS Scopus РИНЦ ANCAN OpenAlex

Full text from publisher

Submitted:	Jul 30, 2008
Accepted:	Oct 17, 2008
Published online:	Dec 18, 2008
Published print:	Jan 29, 2009

Web of science:	WOS:000262665300005
Scopus:	2-s2.0-60549088367
Elibrary:	13603190
Chemical Abstracts:	2008:1519056
Chemical Abstracts (print):	150:73193
OpenAlex:	W2134930439

DB	Citing
Web of science	17
Scopus	17
Elibrary	16
OpenAlex	19