Structural studies of cytochrome b sub 5 : Complete sequence-specific resonance assignments for the trypsin-solubilized microsomal ferrocytochrome b sub 5 obtained from pig and calf

Journal Article · Tue Feb 06 00:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00457a025· OSTI ID:6697875

Guiles, R D; Waskell, L ^[1]; Altman, J; Kuntz, I D ^[2]

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1. Univ. of California, San Francisco (USA) Veterans Administration Medical Center, San Francisco, CA (USA)
2. Univ. of California, San Francisco (USA)

The authors report complete sequence-specific proton resonance assignments for the trypsin-solubilized microsomal ferrocytochrome b{sub 5} obtained from calf liver. In addition, sequence-specific resonance assignments for the main-chain amino acid protons (i.e., C{sup {alpha}}, C{sup {beta}}, and amide protons) are also reported for the porcine cytochrome b{sub 5}. Assignment of the majority of the main-chain resonances was rapidly accomplished by automated procedures that used COSY and HOHAHA peak coordinates as input. Long side chain amino acid spin system identification was facilitated by long-range coherence-transfer experiments (HOHAHA). Problems with resonance overlap were resolved by examining differences between the two-dimensional 500-MHz NMR spectra of rabbit, pig, and calf proteins and by examining the temperature-dependent variation of amide proton resonances. Calculations of the aromatic ring-current shifts for protons that the X-ray crystal structure indicated were proximal to aromatic residues were found to be useful in corroborating assignments, especially those due to the large shifts induced by the heme. Assignment of NOESY cross peaks was greatly facilitated by a prediction of intensities using a complete relaxation matrix analysis based on the crystal structure. These results suggest that the single-crystal X-ray structure closely resembles that of the solution structure although there is evidence that the solution structure has a more dynamic character.

• OSTI ID: 6697875
• Journal Information: Biochemistry; (USA), Vol. 29:5; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CYTOCHROMES
NUCLEAR MAGNETIC RESONANCE
CALVES
CHEMICAL SHIFT
MICROSOMES
MOLECULAR STRUCTURE
OVERHAUSER EFFECT
SWINE
X-RAY DIFFRACTION
ANIMALS
CATTLE
CELL CONSTITUENTS
COHERENT SCATTERING
DIFFRACTION
DOMESTIC ANIMALS
MAGNETIC RESONANCE
MAMMALS
ORGANIC COMPOUNDS
ORGANOIDS
PIGMENTS
PROTEINS
RESONANCE
RIBOSOMES
RUMINANTS
SCATTERING
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics