Banci L, Bertini I, Cambria M T, Capozzi F, Dikiy A
Department of Chemistry, University of Florence, Italy.
Eur J Biochem. 1994 Jan 15;219(1-2):663-9. doi: 10.1111/j.1432-1033.1994.tb19982.x.
1H two-dimensional NMR spectroscopy has been applied to the oxidized form of cytochrome c 551 from Rhodocyclus gelatinosus, which is paramagnetic with S = 1/2. The investigation has allowed a complete and unambiguous assignment of the heme protons and some residues around the heme. We have learned that: the conformation of the axial methionine is equal to that of horse heart cytochrome c and different from two isoenzymes of the same cytochrome c 551 from a different strain; pKa of 6.6 +/- 0.3 has been detected through the shift variations of seventh propionate protons. The detailed differences with other cytochromes c in the hyperfine shifts are discussed.
二维¹H核磁共振光谱已应用于来自嗜热栖热放线菌的细胞色素c 551的氧化形式，该形式具有顺磁性，自旋量子数S = 1/2。该研究使得能够对血红素质子以及血红素周围的一些残基进行完整且明确的归属。我们了解到：轴向甲硫氨酸的构象与马心细胞色素c的构象相同，与来自不同菌株的同一细胞色素c 551的两种同工酶不同；通过第七个丙酸质子的位移变化检测到pKa为6.6±0.3。讨论了超精细位移中与其他细胞色素c的详细差异。
