CHEMICAL SYNTHESIS OF CYTOCHROME C--EVOLUTION OF CYTOCHROME C

真核生物的细胞色素c是同源的，含有不变性。 氨基酸序列中约有20%的氨基酸。对这一概念的理解 这些氨基酸被自然界选中的原因将有助于 要了解这种蛋白质的重要性质对于 细胞呼吸。研究这一原因的一种方法是 将单个不变氨基酸替换为其他氨基酸 化学合成，并考察其对蛋白质的影响。 结构-功能-动力学。在合成过程中涉及两个主要问题 用Merrifield固相法测定细胞色素c，首次将两种方法连接起来 形成细胞色素c的片段，第二，立体化学特异性 血红素与细胞色素c的共价结合。 前几年，第二个问题已经通过寻找和解决 从线粒体中溶解细胞色素c合成酶。我们现在是 关注第一个问题。 Corradin和Harbury已经证明了血红素片段[65-HSE-内酯](1-65) 和通过用马的CNBR处理而获得的阿普草胺(66-104) 如果血红素被还原以促进形成，细胞色素c可以重新结合。 甲硫氨酸80-S-血红素键。我们之前的研究表明， 血红素片段铁或铁(1-25)H和凋亡素C形成产生性 很复杂。因为我们在另一份报告中描述的研究表明 亮氨酸32，蛋氨酸80-S-血红素铁键，可能还有色氨酸 59个参与了耦合作用以稳定它们的原子 坐标，配基[65-HSE-内酯](1-65)和(66-104)可以形成 如果亚铁血红素片段(1-25)是 现在时。这样形成的络合物反过来又会促进 安非他酮[65-HSE-内酯](1-65)的高丝氨酸-内酯 脱氢酶(66-104)的α-氨基，形成脱细胞色素c [65-HSE](1-104)。事实上，我们已经以40%的效率实现了这一点。 产物与血红素片段(1-25)-H形成产物性络合物。

Cytochrome c of eucaryotic species are homologous and contain invariant amino acides in some 20% of the amino acid sequence. Understanding of the reason on which these amino acids have been selected by nature would help to understand the important properties of this protein essential for cellular respiration. An approach to the study of this reason is to replace the individual invariant amino acids with other amino acids by chemical synthesis and examine the effect on the structure-function-dynamics. Two major problems are involved in synthesis of cytochrome c by the Merrifield solid phase method, first joining of two fragments to form apocytochrome c and second, stereochemically specific covalent attachment of heme to apocytochrome c. As described in the previous years, the second problem has been solved by finding and solubilizing cytochrome c synthetase from mitochondria. We are now concerned with the first. Corradin and Harbury have shown that heme fragment [65-Hse-lactone] (1-65) and apofragment (66-104) obtained by treatment with CNBr of horse cytochrome c can be rejoined if the heme is reduced to facilitate formation of the methionine 80-S-heme bond. Our previous studies have shown that heme fragment ferri or ferro (1-25)H and apocytochrome c form a productive complex. Since our studies described in another report have indicated that leucine 32, the methionine 80-S-heme iron bond and probably also tryptophan 59 are involved in coupled interactions to stablize their atomic coordinates, apofragments [65-Hse-lactone](1-65) and (66-104) may form an ordered complex through this coupling if ferro heme fragment (1-25) is present. The complex thus formed would in turn facilitate the reaction of the homoserine-lactone of apofragment [65-Hse-lactone](1-65) with the Alpha-NH2-group of apofragment (66-104) to form apocytochrome c [65-Hse](1-104). Indeed, we have attained this joining in 40% efficiency. The product formed a productive complex with heme fragment (1-25)-H.