Heme methyl hyperfine shift pattern as a probe for determining the orientation of the functionally relevant proximal histidyl imidazole with respect to the heme in hemoproteins

FEBS Letters

Chûjô, Riichirô²  Suzuki, Tomohiko¹  Nanai, Norishige²  Yamamoto, Yasuhiko² 

[1] Department of Biology, Faculty of Science, Kochi University, Kochi 780, Japan;Department of Biomolecular Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152, Japan

关键词: NMR;    Myoglobin;    Heme methyl resonance;    Heme electronic structure;    Proximal histidyl imidazole orientation;    NMR;    nuclear magnetic resonance;    1H-13C COSY;    1H-13C heteronuclear shift correlated spectroscopy;    Mb;    myoglobin;    MbCN;    met-cyano form of myoglobin;    SWMb;    sperm whale myoglobin;    ALMb;    Aplysia limacma myoglobin;    CYT-c;    horse heart eytochrome c;    HRP;    horseradish peroxidase;    ppm;    parts per million;    DSS;    2;    2-dimethyl-2-silapentane-5 -sulfonate;   

DOI  :  10.1016/0014-5793(90)80778-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Heme methyl ¹H and ¹³C resonances of met-cyano form of myoglobin from the shark, Geleorhinus japonicus (GJMbCN), have been assigned via ¹H-¹³C heteronuclear shift correlated spectroscopy (COSY) connectivities and their hyperfine shifts were compared with those of the corresponding resonances of some hemoproteins. Variation of the heme methyl ¹H hyperfine shift pattern correlates well with the angle (Φ) between the projection of the proximal histidyl imidazole plane onto the heme plane and the N_II-Fe-N_iv vector. The alteration of the interaction of the heme peripheral side-chains and/or the iron-bound ligand with the surrounding amino acid residues cannot account for large differences in the shifts of the corresponding heme methyl resonances between GJMbCN and sperm whale MbCN. Since the heme methyl ¹H shifts for GJMbCN fall in between those of the corresponding resonances for sperm whale Mb and Aplysia limacma Mb in which the Φ values have been reported to be 19° and 29°, respectively, the Φ value in GJMb is estimated to be slightly larger than 19°.

【 授权许可】

Unknown