Identification of the altered pyrrole in the isomeric sulfmyoglobins: hyperfine shift patterns as indicators of ring saturation in ferric chlorins

Journal Article · Tue Mar 08 04:00:00 EST 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00405a016· OSTI ID:5408951

Chatfield, M J; La Mar, G N; Smith, K M; Leung, H K; Pandey, R K

Analysis of the /sup 1/H NMR hyperfine shift patterns of isomeric sulfmyoglobins is carried out in the met-aquo and met-cyano states to determine the site of saturation in each protein. The utility of the patterns for structure elucidation is established by specific deuterium labeling of heme methyls of the terminal base product. On the basis of the know saturation of ring B in this isomer. The methyl resonance of the saturated ring is found to have strongly attenuated contact shift. Thus, the heme methyl contact shift pattern is diagnostic for the saturated pyrrole in the high-spin state. This rationale is then applied to analyze the assigned NMR spectra of the initial and terminal acid sulfmyoglobin products, revealing that the same ring B is saturated in each isomer. In contrast, the heme methyl contact shift pattern in low-spin ferric complexes reveals that the methyls both on the affected pyrrole and on the trans pyrrole are influenced similarly on sulfmyoglobin formation, precluding the use of this methyl shift pattern as a unique indicator of the site of saturation. Identification of exchangeable proximal histidine resonances for met-aquo sulfmyoglobin complexes with shifts similar to that in native myoglobin dictates inconsequential axial alterations in the sulfmyoglobins, while location of downfield meso proton resonances analogous to those of the native protein demonstrates the retention of the coordinate water in the active site of met-sulfmyoglobin.

• Research Organization: Univ. of California, Davis (USA)
• OSTI ID: 5408951
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:5; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AROMATICS
AZOLES
BARYONS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLORINS
DERIVATIZATION
ELEMENTARY PARTICLES
FERMIONS
GLOBIN
HADRONS
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
HYPERFINE STRUCTURE
MAGNETIC RESONANCE
MYOGLOBIN
NITROSO COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHENOLS
PIGMENTS
POLYPHENOLS
PORPHYRINS
PROTEINS
PROTONS
PYRROLES
RESONANCE