Solution structure of the B form of oxidized rat microsomal cytochrome b5 and backbone dynamics via 15N rotating-frame NMR-relaxation measurements -: Biological implications

被引：27

作者：

Arnesano, F ^{[1
]}

Banci, L ^{[1
]}

Bertini, I ^{[1
]}

Felli, IC ^{[1
]}

Koulougliotis, D ^{[1
]}

机构：

[1] Univ Florence, Dept Chem, I-50121 Florence, Italy

来源：

EUROPEAN JOURNAL OF BIOCHEMISTRY | 1999年 / 260卷 / 02期

关键词：

backbone dynamics; cytochrome b(5); oxidized B form; solution structure;

D O I：

10.1046/j.1432-1327.1999.00167.x

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Cytochrome b(5) in solution has two isomers (A and B) differing by a 180 degrees rotation of the protoporphyrin IX plane around the axis defined by the alpha and gamma meso protons. Homonuclear and heteronuclear NMR spectroscopy has been employed in order to solve the solution structure of the minor (B) form of the oxidized state of the protein and to probe its backbone dynamics in the mu s-ms timescale in both oxidation states. A family of 40 conformers has been obtained using 1302 meaningful NOEs and 220 pseudocontact shifts and is characterized by high quality and good resolution (rmsd to the mean structure of 0.055 +/- 0.009 nm and 0.103 +/- 0.011 nm for backbone and heavy atoms, respectively). Extensive comparisons of the structural and dynamics changes associated with the A-to-B form interconversion for both oxidation states were subsequently performed. Propionate 6 experiences a redox-state-dependent reorientation as does propionate 7 in the A form. Significant insights are obtained into the role of the protein frame for efficient biological function and backbone mobility is proposed to be one of the factors that could control the reduction potential of the heme.

引用

页码：347 / 354

页数：8

共 43 条

[11]

2-B

[12] PSEUDYANA for NMR structure calculation of paramagnetic metalloproteins using torsion angle molecular dynamics [J].