NMR studies of the heme pocket conformations of monomeric hemoglobins from Glycera dibranchiata. Implications for ligand binding.
NMR studies of the heme pocket conformations of monomeric hemoglobins from Glycera dibranchiata. Implications for ligand binding.
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来自 Glycera dibranchiata 的单体血红蛋白的血红素袋构象的 NMR 研究。
DOI：
10.1111/j.1432-1033.1987.tb13529.x
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Wright,PE
中科院分区：
文献类型：
--
作者：
Cooke,RM;Dalvit,C;Narula,SS;Wright,PE
Two‐dimensional1H‐NMR methods have been used to assign side‐chain resonances for the tryptophan residues and for several amino acids located in the heme pockets of the carbon monoxide complexes of the major monomeric hemoglobins fromGlycera dibranchiata. The NMR spectra reveal a high degree of conservation of the heme pocket structure in the different hemoglobins. However some conformational differences are evident and residues at positions B10 and G8 on the distal side of the heme pocket are not conserved. From the present NMR studies it appears that the monomericG. dibranchiatahemoglobin examined by X‐ray crystallography [Padlan, E. A. & Love, W. (1974)J. Biol. Chem. 249, 4067–4078] corresponds to HbC. Except that the orientation of the heme in solution is the reverse of that reported in the crystal structure, there is a close correspondence between the heme pocket structure in the crystal and in solution. The proximal histidine coordination geometry is almost identical in the CO complexes of the three monomeric hemoglobins studied. Distal residues are strongly implicated in determining the observed kinetic differences in ligand binding reactions. In particular, steric crowding of the ligand binding site in hemoglobin A is probably a major factor in the slower kinetics of this component.
