Timkovich R, Vavra M R
Biochemistry. 1985 Sep 10;24(19):5189-96. doi: 10.1021/bi00340a035.
The 1H NMR spectra of ferrous sulfmyoglobin, metsulfmyoglobin, and ferric cyanosulfmyoglobin were obtained at 300 MHz. Hyperfine-shifted resonances are observed in the case of metsulfmyoglobin and ferric cyanosulfmyoglobin that have line widths and cover a chemical shift range that are comparable to the corresponding forms of normal myoglobin. Two methyl resonances are observed in the spectrum of ferric cyanosulfmyoglobin at 44.19 and 25.48 ppm (25 degrees C, pH 8.3) that have been assigned to heme methyls at the 8- and 5-positions on the basis of pH titration effects homologous to the corresponding methyl resonances in ferric cyanomyoglobin. Examination of aromatic region resonances and the pH titration profiles of histidine resonances lead to the conclusion that the overall conformation of sulfmyoglobin was highly homologous to that of normal myoglobin and afforded assignments of histidine residues of the former. The most likely position for the addition of a sulfur atom to the heme of sulfmyoglobin is pyrrole ring A, with ring B a possible, but less likely, alternative.
在300兆赫下获得了亚铁硫肌红蛋白、高铁硫肌红蛋白和高铁氰化硫肌红蛋白的1H核磁共振谱。在高铁硫肌红蛋白和高铁氰化硫肌红蛋白的情况下观察到超精细位移共振，其线宽和化学位移范围与正常肌红蛋白的相应形式相当。在高铁氰化硫肌红蛋白的光谱中，在44.19和25.48 ppm（25℃，pH 8.3）处观察到两个甲基共振，根据与高铁氰化肌红蛋白中相应甲基共振同源的pH滴定效应，它们被指定为8位和5位的血红素甲基。对芳香区共振和组氨酸共振的pH滴定曲线的研究得出结论，硫肌红蛋白的整体构象与正常肌红蛋白高度同源，并确定了前者组氨酸残基的归属。硫原子添加到硫肌红蛋白血红素上最可能的位置是吡咯环A，环B是一种可能但可能性较小的选择。
