Mabbutt B C, Wright P E
Biochim Biophys Acta. 1985 Nov 29;832(2):175-85. doi: 10.1016/0167-4838(85)90329-2.
Assignments of resonances of the heme and distal amino acid protons in spectra of the CO and O2 complexes of sperm whale myoglobin are reported. These resonances provide information on the conformation of the heme pocket. For oxymyoglobin, the assignments of the heme meso protons disagree with those proposed previously on the basis of partial deuteration experiments. Rapid ring flips about the C beta-C gamma bond are detected for Phe-CD1. Recent claims for two conformational substates of valine-E11 in carbonmonoxymyoglobin (Bradbury, J.H. and Carver, J.A. (1984) Biochemistry 23, 4905-4913) are shown to be in error. The pK of His-97 (FG3) in carbonmonoxymyoglobin has been determined (pK = 5.9). This residue appears to influence many spectroscopic properties of myoglobin. The distal His-E7 in carbonmonoxymyoglobin has pK less than 5.0. Differences in the heme pocket conformation in the CO complexes of myoglobin and leghemoglobin are discussed. These differences may be influential in O2 and CO association reactions.
报道了抹香鲸肌红蛋白的一氧化碳（CO）和氧气（O₂）复合物光谱中血红素及远端氨基酸质子的共振归属。这些共振提供了血红素口袋构象的信息。对于氧合肌红蛋白，血红素中位质子的归属与之前基于部分氘代实验提出的归属不一致。检测到苯丙氨酸-CD1围绕Cβ-Cγ键的快速环翻转。已证明最近关于一氧化碳肌红蛋白中缬氨酸-E11的两种构象亚态的说法（Bradbury, J.H.和Carver, J.A.（1984年）《生物化学》23, 4905 - 4913）是错误的。已测定一氧化碳肌红蛋白中组氨酸-97（FG3）的pK值（pK = 5.9）。该残基似乎影响肌红蛋白的许多光谱性质。一氧化碳肌红蛋白中的远端组氨酸-E7的pK值小于5.0。讨论了肌红蛋白和豆血红蛋白的CO复合物中血红素口袋构象的差异。这些差异可能对O₂和CO结合反应有影响。
