Detection of two histidyl ligands to Cu[sub A] of cytochrome oxidase by 35-GHz ENDOR. [sup 14,15]N and [sup 63,65]Cu ENDOR studies of the Cu[sub A] site in bovine heart cytochrome aa[sub 3] and cytochromes caa[sub 3] and ba[sub 3] from Thermus thermophilus

Journal Article · Tue Nov 16 23:00:00 EST 1993 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00076a053· OSTI ID:7301970

Gurbiel, R J ^[1]; Fann, Y C; Werst, M M; Doan, P E; Hoffman, B M ^[2]; Surerus, K K ^[3]; Musser, S M; Chan, S I ^[4]; Fee, J A ^[5]

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1. Northwestern Univ., Evanston, IL (United States) Jagiellonian Univ., Krakow (Poland)
2. Northwestern Univ., Evanston, IL (United States)
3. Los Alamos National Lab., NM (United States)
4. California Inst. of Technology, Pasadena, CA (United States)
5. Los Alamos National Lab., NM (United States) Univ. of California, La Jolla, CA (United States)

To study the ligation of the Cu[sub A] site of heme-copper terminal oxidases, we have performed ENDOR measurements at X-band (9-GHz) and 35-GHz microwave frequencies on the three titled enzymes. The 35-GHz measurements provide complete spectral separation of the [sup 1]H and [sup 14]N resonances and permit analysis of the field dependence of the [sup 14]N ENDOR for each enzyme. The results indicate that two nitrogenous ligands were quite unequal hyperfine couplings are ligated to Cu[sub A] in each of the enzymes studied. We have also examined cytochrome caa[sub 3] isolated from His Thermus cells grown in the presence of D,L,-[[delta],[epsilon]-[sup 15]N[sub 2]]histidine. The 35-GHz Cu[sub A] ENDOR spectrum of this protein includes [sup 15]N ENDOR resonances whose frequencies confirm the presence of two nitrogeneous ligands; comparison with the [sup 14]N ENDOR spectra further shows that the ligand with the larger hyperfine coupling (N1) displays well-resolved [sup 14]N quadrupole splitting. The theory for simulating frozen-solution ENDOR spectra as refined here permits a determination of both hyperfine and quadrupole tensors for N1 of all three enzymes. These indicate that the bonding parameters and geometry of Cu[sub A] are well conserved. 55 refs., 7 figs., 1 tab.

• OSTI ID: 7301970
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 115:23; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
AMINO ACIDS
AZOLES
CARBOXYLIC ACIDS
COMPLEXES
COPPER COMPLEXES
CYTOCHROME OXIDASE
CYTOCHROMES
ENZYMES
HAEM DEHYDROGENASES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
IMIDAZOLES
ISOTOPES
LIGANDS
LIGHT NUCLEI
MATHEMATICAL MODELS
NITROGEN 14
NITROGEN ISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
PIGMENTS
PROTEINS
SPECTROSCOPY
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES