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首页> 外文期刊>Journal of bacteriology >Characterization of a 12-Kilodalton Rhodanese Encoded byglpE of Escherichia coli and Its Interaction with Thioredoxin
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Characterization of a 12-Kilodalton Rhodanese Encoded byglpE of Escherichia coli and Its Interaction with Thioredoxin

机译：大肠杆菌的glpE编码的12公斤罗丹语的表征及其与硫氧还蛋白的相互作用

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Rhodaneses catalyze the transfer of the sulfane sulfur from thiosulfate or thiosulfonates to thiophilic acceptors such as cyanide and dithiols. In this work, we define for the first time the gene, and hence the amino acid sequence, of a 12-kDa rhodanese fromEscherichia coli. Well-characterized rhodaneses are comprised of two structurally similar ca. 15-kDa domains. Hence, it is thought that duplication of an ancestral rhodanese gene gave rise to the genes that encode the two-domain rhodaneses. The glpEgene, a member of the sn-glycerol 3-phosphate (glp) regulon of E. coli, encodes the 12-kDa rhodanese. As for other characterized rhodaneses, kinetic analysis revealed that catalysis by purified GlpE occurs by way of an enzyme-sulfur intermediate utilizing a double-displacement mechanism requiring an active-site cysteine. TheKm s for SSO3 2? and CN? were 78 and 17 mM, respectively. The apparent molecular mass of GlpE under nondenaturing conditions was 22.5 kDa, indicating that GlpE functions as a dimer. GlpE exhibited ak cat of 230 s?1. Thioredoxin 1 from E. coli, a small multifunctional dithiol protein, served as a sulfur acceptor substrate for GlpE with an apparentKm of 34 μM when thiosulfate was near itsKm , suggesting that thioredoxin 1 or related dithiol proteins could be physiological substrates for sulfurtransferases. The overall degree of amino acid sequence identity between GlpE and the active-site domain of mammalian rhodaneses is limited (～17%). This work is significant because it begins to reveal the variation in amino acid sequences present in the sulfurtransferases. GlpE is the first among the 41 proteins in COG0607 (rhodanese-related sulfurtransferases) of the database Clusters of Orthologous Groups of proteins (http://www.ncbi.nlm.nih.gov/COG/) for which sulfurtransferase activity has been confirmed.
机译：硫丹酮催化硫磺从硫代硫酸盐或硫代磺酸盐到亲硫性受体如氰化物和二硫醇的转移。在这项工作中，我们首次定义了来自大肠杆菌的12 kDa罗丹酶的基因及其氨基酸序列。表征良好的若丹酮由两个结构相似的ca组成。 15 kDa域。因此，认为祖传罗丹酶基因的重复产生了编码两结构域罗丹烷的基因。 glpE 基因是 E的 sn -3-磷酸甘油（ glp ）调节子的成员。大肠埃希菌，编码12 kDa罗丹色。对于其他表征的若丹宁，动力学分析表明，通过纯化的GlpE的催化是通过酶-硫中间体进行的，该酶-硫中间体利用需要活性位的半胱氨酸的双置换机制。 SSO 3 2？和CN ？的 K m s分别为78和分别为17 mM。在非变性条件下，GlpE的表观分子量为22.5 kDa，表明GlpE充当二聚体。 GlpE表现出230 s ？1 的 k cat 。来自 E的硫氧还蛋白1。小多功能二硫醇蛋白大肠杆菌作为GlpE的硫受体底物，当硫代硫酸盐接近其时，表观 K m 为34μM K m ，表明硫氧还蛋白1或相关的二硫醇蛋白可能是硫转移酶的生理底物。 GlpE与哺乳动物红丹烯酶活性位点结构域之间氨基酸序列同一性的总体程度是有限的（〜17％）。这项工作意义重大，因为它开始揭示出硫转移酶中氨基酸序列的变化。 GlpE是数据库直系同源蛋白质簇（http://www.ncbi.nlm.nih.gov/COG/）的数据库COG0607（与罗丹苏丹语相关的硫转移酶）中的41种蛋白质中的第一种，其硫转移酶活性已得到证实。 。

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