Makinen M W, Houtchens R A, Caughey W S
Proc Natl Acad Sci U S A. 1979 Dec;76(12):6042-6. doi: 10.1073/pnas.76.12.6042.
The configuration of the heme-carbonyl group upon binding of carbon monoxide to sperm whale myoglobin (Mb) in crystals is evaluated on the basis of infrared spectroscopic methods. Multiplets of the totally symmetric C-O stretching mode are observed for the heme-bound ligand near 1933, 1944, and 1967 cm-1, corresponding to three different heme-carbonyl conformers. Variations in the relative proportions of these conformers can be induced by incorporation of small fractions of metMb or deoxyMb into MbCO crystals. The configuration of the iron-carbonyl with respect to the immediate coordination environment of the heme iron is assigned for each v(CO) stretching frequency on the basis of a detailed comparison of the three-dimensional structures of the heme environments of MbCO, metMb, and deoxyMb defined by crystallographic methods. The structures of the three heme-carbonyl conformers account for the v(CO) infrared absorption bands that can be observed for MbCO in solution.
基于红外光谱方法,对一氧化碳与晶体中的抹香鲸肌红蛋白(Mb)结合时血红素 - 羰基基团的构型进行了评估。在1933、1944和1967 cm-1附近观察到与血红素结合的配体的全对称C - O伸缩模式的多重峰,对应于三种不同的血红素 - 羰基构象体。通过将少量高铁肌红蛋白(metMb)或脱氧肌红蛋白(deoxyMb)掺入MbCO晶体中,可以诱导这些构象体相对比例的变化。基于通过晶体学方法确定的MbCO、metMb和deoxyMb血红素环境的三维结构的详细比较,为每个v(CO)伸缩频率指定了相对于血红素铁直接配位环境的铁 - 羰基构型。三种血红素 - 羰基构象体的结构解释了在溶液中可观察到的MbCO的v(CO)红外吸收带。