Solution structural characterization of cyanometmyoglobin: Resonance assignment of heme cavity residues by two-dimensional NMR

Journal Article · Mon Feb 12 23:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00458a028· OSTI ID:7008953

Emerson, S D; La Mar, G N ^[1]

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1. Univ. of California, Davis (USA)

Steady-state nuclear Overhauser effects (NOE), two-dimensional (2D) nuclear Overhauser effect spectroscopy (NOESY), and 2D spin correlation spectroscopy (COSY) have been applied to the fully paramagnetic low-spin, cyanide-ligated complex of sperm whale ferric myoglobin to assign the majority of the heme pocket side-chain proton signals and the remainder of the heme signals. It is shown that the 2D NOESY map reveals essentially all dipolar connectivities observed in ordinary 1D NOE experiments and expected on the basis of crystal coordinates, albeit often more weakly than in a diamagnetic analogue. For extremely broad ({approximately}600-Hz) and rapidly relaxing (T{sub 1} {approximately} 3 ms) signals which show no NOESY peaks, the authors demonstrate that conventional steady-state NOEs obtained under very rapid pulsing conditions still allow detection of the critical dipolar connectivities that allow unambiguous assignments. Numerous critical COSY cross peaks between strongly hyperfine-shifted peaks were resolved and assigned. In all, 95% (53 of 56 signals) of the total proton sets within {approximately}7.5 {angstrom} of the iron, the region experiencing the strongest hyperfine shifts and paramagnetic relaxation, are now unambiguously assigned. Hence it is clear that the 2D methods can be profitably applied to paramagnetic proteins. The scope and limitations of such application are discussed. The resulting hyperfine shift pattern for the heme confirmed expectations based on model compounds.

• OSTI ID: 7008953
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:6; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
CARBOXYLIC ACIDS
CHEMICAL SHIFT
ELEMENTARY PARTICLES
FERMIONS
GLOBINS
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
MYOGLOBIN
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OVERHAUSER EFFECT
PIGMENTS
PORPHYRINS
PROTEINS
PROTONS
RESONANCE