Determination of iron-ligand bond lengths in ferric and ferrous horse heart cytochrome c using multiple scattering analyses of XAFS data

被引:31
作者
Cheng, MC [1 ]
Rich, AM [1 ]
Armstrong, RS [1 ]
Ellis, PJ [1 ]
Lay, PA [1 ]
机构
[1] Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia
关键词
D O I
10.1021/ic990395r
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
X-ray absorption fine structure (XAFS) data were obtained from frozen aqueous solutions (10 K) of horse heart ferri- and ferrocyt c. Models of the structure about the Fe center were refined to optimize the fit between the observed XAFS in the range 0 less than or equal to k less than or equal to 16.3 Angstrom(-1) and the XAFS calculated using both single-scattering (SS) and multiple-scattering (MS) calculations. The bond lengths obtained are more accurate and precise than those determined previously for cyt c from various species using X-ray crystallography. The Fe-N bond lengths are 1.98-1.99 Angstrom for both oxidation states of cyt c. The Fe-S bond of ferricyt c (2.33 Angstrom) is significantly longer than that of ferrocyt c (2.29 Angstrom). The small changes in the bond lengths are consistent with the small reorganizational energy required for the fast electron-transfer reaction of cyt c.
引用
收藏
页码:5703 / 5708
页数:6
相关论文
共 38 条