Evans S V, Sishta B P, Mauk A G, Brayer G D
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.
Proc Natl Acad Sci U S A. 1994 May 24;91(11):4723-6. doi: 10.1073/pnas.91.11.4723.
The atomic structure of horse heart cyanomet-sulfmyoglobin C has been established by x-ray crystallographic techniques to a resolution of 2.0 A with an R value of 0.129. The protoheme IX prosthetic group of this thermodynamically stable sulfmyoglobin derivative has been converted to a chlorin in which the pyrrole ring bearing the 4-vinyl group is saturated and possesses an exocyclic thiolene ring. This study provides the three-dimensional structure of a protein with an iron-chlorin prosthetic group. The overall conformation of the surrounding polypeptide chain of the modified protein is very similar to that of the native protein. However, the addition of the sulfur atom has caused a distortion of the prosthetic group from that in the native protein to result in the repositioning of the side chains of some residues in the heme pocket.
马心氰化高铁硫肌红蛋白C的原子结构已通过X射线晶体学技术确定，分辨率为2.0埃，R值为0.129。这种热力学稳定的硫肌红蛋白衍生物的原血红素IX辅基已转化为二氢卟酚，其中带有4-乙烯基的吡咯环饱和并具有一个环外硫杂环烯环。本研究提供了一种带有铁-二氢卟酚辅基的蛋白质的三维结构。修饰后蛋白质周围多肽链的整体构象与天然蛋白质非常相似。然而，硫原子的添加导致辅基相对于天然蛋白质发生了扭曲，从而导致血红素口袋中一些残基侧链的重新定位。
