A short Fe-Fe distance in peroxodiferric ferritin: Control of Fe substrate versus cofactor decay?

被引:156
作者
Hwang, J
Krebs, C
Huynh, BH
Edmondson, DE
Theil, EC
Penner-Hahn, JE [1 ]
机构
[1] Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA
[2] Emory Univ, Dept Biochem, Atlanta, GA 30322 USA
[3] Emory Univ, Dept Chem, Atlanta, GA 30322 USA
[4] Childrens Hosp Oakland, Res Inst, Oakland, CA 94609 USA
关键词
D O I
10.1126/science.287.5450.122
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The reaction of oxygen with protein diiron sites is important in bioorganic syntheses and biomineralization. An unusually short Fe-Fe distance of 2.53 angstroms was found in the diiron (mu-1,2 peroxodiferric) intermediate that forms in the early steps of ferritin biomineralization. This distance suggests the presence of a unique triply bridged structure. The Fe-Fe distances in the mu-1,2 peroxodiferric complexes that were characterized previously are much longer (3.1 to 4.0 angstroms). The 2.53 angstrom Fe-Fe distance requires a small Fe-O-O angle (similar to 106 degrees to 107 degrees). This geometry should favor decay of the peroxodiferric complex by the release of H2O2 and mu-oxo or mu-hydroxo diferric biomineral precursors rather than by oxidation of the organic substrate. Geometrical differences may thus explain how diiron sites can function either as a substrate (in ferritin biomineralization) or as a cofactor (in O-2 activation).
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页码:122 / 125
页数:4
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