Isolation and amino acid sequence of a monomeric hemoglobin in heart muscle of the bullfrog, Rana catesbeiana.
Isolation and amino acid sequence of a monomeric hemoglobin in heart muscle of the bullfrog, Rana catesbeiana.
复制标题
牛蛙心肌中单体血红蛋白的分离和氨基酸序列。
DOI：
--
复制
发表时间：
1982
影响因子：
4.8
通讯作者：
Fitch
中科院分区：
文献类型：
--
作者：
Nobuyo Maeda;Walter;Fitch
通过Sephadex G-75凝胶过滤和DE 52离子交换柱层析，从牛蛙心肌中分离到一种含血红素的单体蛋白。该蛋白由132个氨基酸残基组成，通过Sephadex G-50凝胶过滤估计其Mr = 14，000。这是迄今为止已知的最短的血红素珠蛋白。从溴化氰片段和胰蛋白酶肽段的氨基酸序列推导出脱辅基蛋白的完整氨基酸序列。为了将其氨基酸序列与珠蛋白超家族中的其它蛋白质比对（Hunt，L. T.的，Hurst-Calderone，S.，和Dayhoff，M. O.（1978）Atlas of Protein Sequence and Structure，第5卷，增刊3，229-249，National Biomedical Research Foundation，华盛顿，华盛顿特区），需要α-血红蛋白共有的三个缺口加上该蛋白质中独特的另外三个缺口。在后者中，一个位于EF区的末端，第二个靠近H区的开始，第三个位于COOH末端。该单体共有62个氨基酸残基，其氨基酸序列与R. catesbeiana（Maruyama，T.，Watt，K. W. K.，和Riggs，A.（1980）J.Biol.Chem.255，3285-3293）。对它和其他球蛋白的系统发育研究清楚地表明，它是通过血红蛋白的基因复制产生的，接近产生α和β基因的复制时间。但是与血红素基团接触的残基是相当保守的，而α 1 β 1、α 1 β 2亚基接触区中的残基被显著取代，经常恢复为肌红蛋白样残基。血液中没有这种单体蛋白，心肌中没有肌红蛋白，可能表明这种蛋白质具有肌红蛋白的功能。
A monomeric heme-containing protein was isolated from heart muscles of the bullfrog, Rana catesbeiana, by gel filtration on Sephadex G-75 followed by DE52 ion-exchange column chromatography. The protein is composed of 132 amino acid residues and has Mr = 14,000 estimated by gel filtration on Sephadex G-50. This is the shortest heme globin so far known. The complete amino acid sequence of the apoprotein was deduced from the amino acid sequences of cyanogen bromide fragments and tryptic peptides. In order to align its amino acid sequence with other proteins in the globin superfamily (Hunt, L. T., Hurst-Calderone, S., and Dayhoff, M. O. (1978) Atlas of Protein Sequence and Structure, Vol. 5, Suppl. 3, 229-249, National Biomedical Research Foundation, Washington, D.C.), three gaps common to alpha-hemoglobin are required plus three more gaps unique in this protein. Of the latter, one is at the end of the EF region, the second near the beginning of the H-region, and the third is at the COOH terminus. With 62 amino acid residues in common, the amino acid sequence of this monomer is more homologous to the alpha-hemoglobin of the tadpole of R. catesbeiana (Maruyama, T., Watt, K. W. K., and Riggs, A. (1980) J. Biol. Chem. 255, 3285-3293), than to any other globin. A phylogenetic study of it and other globins clearly reveals that it arose via a gene duplication of hemoglobin near the time of the duplication that gave rise to the alpha and beta genes. But residues in contact with the heme group are rather conserved while the residues in the alpha 1 beta 1, alpha 1 beta 2 subunit contact regions are significantly substituted, frequently reverting to a myoglobin-like residue. The absence of this monomeric protein from the blood and the absence of myoglobin in heart muscle may indicate the protein functions as a myoglobin.