Phylogenomic analysis of the Giardia intestinalis transcarboxylase reveals multiple instances of domain fusion and fission in the evolution of biotin-dependent enzymes
Phylogenomic analysis of the Giardia intestinalis transcarboxylase reveals multiple instances of domain fusion and fission in the evolution of biotin-dependent enzymes
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DOI：
10.1159/000070268
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发表时间：
2003-01-01
影响因子：
1.2
通讯作者：
Galperin, MY
中科院分区：
文献类型：
--
作者：
Jordan, IK;Henze, K;Galperin, MY
对真核生物肠贾第鞭毛虫的丙酮酸羧基转移酶类似蛋白的编码基因进行了序列分析，发现该蛋白含有1,338个氨基酸，由乙酰辅酶A羧基转移酶(ACCT)、丙酮酸羧基转移酶(PycB)和生物素羧基载体蛋白(BCCP)结构域组成，连接在一条多肽链上。这种特殊的结构域组合以前只在弗罗德赖氏丙酸丙酸杆菌的甲基丙二酰辅酶A：丙酮酸转羧酶中看到，其中每个结构域由一个单独的基因编码，并形成一个单独的亚基。为了深入了解肠杆菌酶的进化起源和生化功能，我们将其结构域组成与其他依赖生物素的酶进行了比较，并对其每个结构域进行了系统发育分析。结果表明：(1)BCCP结构域的进化包括多个结构域融合事件，导致ACCT-BCCP和PYCCB-BCCP结构域结合；(2)在不同的原核谱系中，丙酮酸羧化酶和草酰乙酸酯脱羧酶中的PYcB和BCCP结构域的融合发生了几次独立的情况，这可能是由于对这些基因共表达的选择性压力；(3)由于新测序的生物素依赖的酶在序列数据库中经常被错误地注释，它们的注释要么是羧基酶，要么是脱羧酶，要么是转羧酶，要么依赖于对其结构域组成的详细分析，相应基因的操纵子组织，特定基因组中的基因含量，以及系统发育分析。版权所有(C)2003 S.Karger AG，巴塞尔。
Sequencing of the gene encoding a pyruvate carboxylase-like protein from the amitochondrial eukaryote Giardia intestinalis revealed a 1,338 aa protein composed of acetyl-CoA carboxyltransferase (ACCT), pyruvate carboxyltransferase (PycB), and biotin carboxyl carrier protein (BCCP) domains, linked in a single polypeptide chain. This particular domain combination has been previously seen only in the methylmalonyl-CoA:pyruvate transcarboxylase from Propionibacterium freudenreichii, where each of these domains is encoded by an individual gene and forms a separate subunit. To get an insight into the evolutionary origin and biochemical function of the G. intestinalis enzyme, we compared its domain composition to those of other biotin-dependent enzymes and performed a phylogenetic analysis of each of its domains. The results obtained indicate that: (1) evo-lution of the BCCP domain included several domain fusion events, leading to the ACCT-BCCP and PycB-BCCP domain combinations; (2) fusions of the PycB and BCCP domains in pyruvate carboxylases and oxaloacetate decarboxylases occurred on several independent occasions in different prokaryotic lineages, probably due to selective pressure towards co-expression of these genes, and (3) because newly sequenced biotin-dependent enzymes are often misannotated in sequence databases, their annotation as either carboxylases, decarboxylases, or transcarboxylases has to rely on detailed analysis of their domain composition, operon organization of the corresponding genes, gene content in the particular genome, and phylogenetic analysis. Copyright (C) 2003 S. Karger AG, Basel.