An x-ray absorption study of the iron site in bacterial photosynthetic reaction centers

Biophysical Journal
G BunkerW W Parson

Abstract

Measurements were made of the extended x-ray absorption fine structure (EXAFS) of the iron site in photosynthetic reaction centers from the bacterium Rhodopseudomonas sphaeroides. Forms with two quinones, two quinones with added o-phenanthroline, and one quinone were studied. Only the two forms containing two quinones maintained their integrity and were analyzed. The spectra show directly that the added o-phenanthroline does not chelate the iron atom. Further analysis indicates that the iron is octahedrally coordinated by nitrogen and/or oxygen atoms located at various distances, with the average value of about 2.14 A. The analysis suggests that most of the ligands are nitrogens and that three of the nitrogen ligands belong to histidine rings. This interpretation accounts for several unusual features of the EXAFS spectrum. We speculate that the quinones are bound to the histidine rings in some manner. Qualitative features of the absorption edge spectra also are discussed and are related to the Fe-ligand distance.

Citations

Dec 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·J C WilliamsM I Simon
Nov 1, 1986·Proceedings of the National Academy of Sciences of the United States of America·J P AllenR Huber
Aug 1, 1987·Proceedings of the National Academy of Sciences of the United States of America·J P AllenD C Rees
Nov 1, 1988·Proceedings of the National Academy of Sciences of the United States of America·J P AllenD C Rees
Nov 15, 1991·Proceedings of the National Academy of Sciences of the United States of America·L C WebsterR P Ricciardi
Apr 16, 1996·Proceedings of the National Academy of Sciences of the United States of America·D S AuldB L Vallee
Dec 1, 1989·Journal of Biomolecular Structure & Dynamics·M A Hadwiger, G E Fox
Aug 31, 1988·Biochimica Et Biophysica Acta·S NavaratnamJ F Vliegenthart
May 1, 1989·Physical Review. B, Condensed Matter·M QianI Aksay
Sep 1, 1982·Biochimica Et Biophysica Acta·L Powers

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