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Studies on sulculus tissue hemoglobin evolved from indoleamine 2,3-dioxygenase, a tryptophan-degrading enzyme.

对龈沟组织血红蛋白的研究是由吲哚胺 2,3-双加氧酶（一种色氨酸降解酶）演变而来。

基本信息

批准号：
05640771
负责人：
SUZUKI Tomohiko
金额：
$ 1.28万
依托单位：
Kochi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The abalone Sulculus diversicolor contains abundant myoglobin in buccal mass. The myoglobin consists of 377 amino acid residues and the molecular mass is 41,000Da, which is 2.5 times larger than that of usual myoglobin.Sulculus myoglobin can bind oxygen reversibly, and thus functions as an oxygen carrier. The cDNA-derived amino acid sequence showed no significant homology with those of any other invertebrate myoglobins and hemoglobins, but surprisingly showed 35% homology with a vertebrate tryptophan degrading enzyme, indoleamine dioxygenase (IDO). The gene structure consisting of 14 exons and 13 introns (15.3 kbp) of sulculus myoglobin has been determined. Compared with the gene of human IDO (10 exon-9 intron structure) , the splice junctions of 7 introns were exactly conserved between the two genes, suggesting that these introns have been conserved for at least 600 million years. Sulculus gene has additional 5 introns, one of which is located outside the coding region. The interferon-stimulable response element-like sequence, which is present in many different interferon-stimulated gene promoters, is present in the 5'flanking sequence of Sulculus gene, as in human IDO gene. From these results we conclude that Sulculus myoglobin evolved from a IDO gene. The birth of Sulculus myoglobin must be a typical case of functional convergence. The IDO-like myoglobin is unexpectedly widely distrbuted among gastropodic molluses, such as Sulculus, Nordotis, Battilus and Chlorostoma.

杂色鲍口腔肌团中含有丰富的肌红蛋白。肌红蛋白由377个氨基酸残基组成，分子量为41, 000 Da，是普通肌红蛋白的2.5倍，具有可逆氧结合的功能，是氧的载体。cDNA衍生的氨基酸序列与任何其他无脊椎动物肌红蛋白和血红蛋白的氨基酸序列没有显着的同源性，但令人惊讶的是，与脊椎动物色氨酸降解酶吲哚胺双加氧酶（IDO）显示出35%的同源性。结果表明，该基因由14个外显子和13个内含子组成，长度为15.3kbp。与人类IDO基因（10外显子-9内含子结构）相比，两个基因中有7个内含子的剪接点是完全保守的，表明这些内含子至少已经保守了6亿年。Sulculus基因有5个额外的内含子，其中一个位于编码区之外。存在于许多不同的干扰素刺激的基因启动子中的干扰素刺激的应答元件样序列存在于Sulculus基因的5 '侧翼序列中，如在人IDO基因中一样。从这些结果中，我们得出结论，Sulculus肌红蛋白进化IDO基因。脑沟肌红蛋白的诞生是一个典型的功能性融合的例子。IDO样肌红蛋白广泛分布于沟螺属、诺氏螺属、螺属和绿口螺属等腹足类软体动物中。