Ferricytochrome b5: assignment of heme propionate resonances on the basis of nuclear Overhauser effect measurements and the nature of interprotein contacts with partner redox proteins
Ferricytochrome b5: assignment of heme propionate resonances on the basis of nuclear Overhauser effect measurements and the nature of interprotein contacts with partner redox proteins
复制标题
铁细胞色素 b5：根据核奥弗豪瑟效应测量和蛋白间与伙伴氧化还原蛋白接触的性质来分配丙酸血红素共振
DOI：
10.1021/ja00266a026
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发表时间：
1986
影响因子：
15
通讯作者：
E. Sletten
中科院分区：
文献类型：
--
作者：
S. McLachlan;G. N. Mar;E. Sletten
核Overhauser效应实验已导致thesterospecific指定的亚铁细胞色素b5的血红素丙酸侧链的四个亚甲基质子对。pH敏感的共振已被分配到暴露的血红素吡咯环III上的丙酸亚铁血红素。此外，它已被证明，这个基团是能够结合外来金属离子，并密切参与氧化还原伴侣蛋白的结合位点。的-亚甲基质子超精细位移的模式丙酸酯的结论是不一致的取向从可用的X-射线crystalcoordinates和建议特定的rotationsfor每个侧链。与伴侣氧化还原蛋白质，如细胞色素c或肌红蛋白形成复合物所产生的轻微变化的性质被证明是一致的暴露的6-丙酸羧酸的pK降低。这种减少支持该基团直接参与到与伴侣蛋白的盐桥中。
Nuclear Overhauser effect experiments have lead to thestereospecific assignment of the four methylene proton pairs of the heme propionate side chains in ferricytochrome b5. The pH-sensitive resonances have been assigned to the exposed heme propionate on the heme pyrrole ring III. In addition it has been shown that this group is able to bind extrinsic metal ions and is intimately involved in the binding site for redox partner proteins. The patterns of the-methylene proton hyperfine shifts for both propionates are concluded to be inconsistent with the orientation obtained from available X-ray crystalcoordinates and suggest specific rotationsfor each side chain. The nature of the slight changes resulting from complex formation with partner redox proteins such as cytochrome c or myoglobin is shown to be consistent with a decrease of the pK for the exposed 6-propionate carboxylate. This decrease supports a direct participation of this group in a salt bridge to the partner protein.