Sivakolundu Sivashankar G, Mabrouk Patricia Ann
Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
J Biol Inorg Chem. 2003 May;8(5):527-539. doi: 10.1007/s00775-002-0437-0. Epub 2003 Feb 15.
The complete solution structure of ferrocytochrome c in 30% acetonitrile/70% water has been determined using high-field 1D and 2D (1)H NMR methods and deposited in the Protein Data Bank with codes 1LC1 and 1LC2. This is the first time a complete solution protein structure has been determined for a protein in nonaqueous media. Ferrocyt c retains a native protein secondary structure (five alpha-helices and two omega loops) in 30% acetonitrile. H18 and M80 residues are the axial heme ligands, as in aqueous solution. Residues believed to be axial heme ligands in the alkaline-like conformers of ferricyt c, specifically H33 and K72, are positioned close to the heme iron. The orientations of both heme propionates are markedly different in 30% acetonitrile/70% water. Comparative structural analysis of reduced cyt c in 30% acetonitrile/70% water solution with cyt c in different environments has given new insight into the cyt c folding mechanism, the electron transfer pathway, and cell apoptosis.
利用高场一维和二维氢核磁共振方法确定了亚铁细胞色素c在30%乙腈/70%水体系中的完整溶液结构，并已存入蛋白质数据库，代码为1LC1和1LC2。这是首次在非水介质中确定一种蛋白质的完整溶液结构。亚铁细胞色素c在30%乙腈中保留了天然蛋白质二级结构（五个α螺旋和两个ω环）。与在水溶液中一样，H18和M80残基是轴向血红素配体。在高铁细胞色素c的类碱性构象中被认为是轴向血红素配体的残基，特别是H33和K72，位于靠近血红素铁的位置。在30%乙腈/70%水中，两个血红素丙酸酯的取向明显不同。对30%乙腈/70%水溶液中还原型细胞色素c与不同环境中细胞色素c的比较结构分析，为细胞色素c的折叠机制、电子传递途径和细胞凋亡提供了新的见解。
