Electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the Rieske Fe-S centers of the cytochrome b sub 6 f complex of spinach and the cytochrome bc sub 1 complexes of Rhodospirillum rubrum, Rhodobacter sphaeroides R-26, and bovine heart mitochondria

Journal Article · Tue Feb 19 04:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00221a023· OSTI ID:5596146

Britt, R D; Sauer, K; Klein, M P ^[1]; Knaff, D B; Kriauciunas, A ^[2]; Yu, Changan; Yu, Linda ^[3]; Malkin, R ^[4]

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1. Lawrence Berkeley Lab., CA (USA)
2. Texas Tech Univ., Lubbock (USA)
3. Oklahoma State Univ., Stillwater (USA)
4. Univ. of California, Berkeley (USA)

Electron spin echo envelope modulation (ESEEM) experiments performed on the Rieske Fe-S clusters of the cytochrome b{sub 6}f complex of spinach chloroplasts and of the cytochrome bc{sub 1} complexes of Rhodospirillum rubrum, Rhodobacter sphaeroides R-26, and bovine heart mitochondria show modulation components resulting from two distinct classes of {sup 14}N ligands. At the g = 1.92 region of the Rieske EPR spectrum of the cytochrome b{sub 6}f complex, the measured hyperfine couplings for the two classes of coupled nitrogens are A{sub 1} = 4.6 MHz and A{sub 2} = 3.8 MHz. Similar couplings are observed for the Rieske centers in the three cytochrome bc{sub 1} complexes. These ESEEM results indicate a nitrogen coordination environment for these Rieske Fe-S centers that is similar to that of the Fe-S cluster of a bacterial dioxygenase enzyme with two coordinated histidine ligands. The Rieske Fe-S cluster lacks modulation components from a weakly coupled peptide nitrogen observed in water-soluble spinach ferredoxin. Treatment with the quinone analogue inhibitor DBMIB causes a shift in the Rieske EPR spectrum to g = 1.95 with no alteration in the magnetic couplings to the two nitrogen atoms. However, the ESEEM pattern of the DBMIB-altered Rieske EPR signal shows evidence of an additional weakly coupled nitrogen similar to that observed in the spinach ferrodoxin ESEEM patterns.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5596146
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:7; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
AZOLES
BACTERIA
BODY
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CATTLE
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLOROPLASTS
CYTOCHROMES
DOMESTIC ANIMALS
ELECTRON SPIN RESONANCE
FOOD
HEART
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYPERFINE STRUCTURE
IMIDAZOLES
ISOTOPES
LIGANDS
LIGHT NUCLEI
MAGNETIC RESONANCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MAMMALS
MICROORGANISMS
MITOCHONDRIA
NITROGEN 14
NITROGEN ISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PIGMENTS
PLANTS
PROTEINS
RESONANCE
RHODOSPIRILLUM
RUMINANTS
SPINACH
STABLE ISOTOPES
SYNTHESIS
VEGETABLES
VERTEBRATES