Chloroplast elongation factor Ts pro-protein is an evolutionarily conserved fusion with the S1 domain-containing plastid-specific ribosomal protein-7
Chloroplast elongation factor Ts pro-protein is an evolutionarily conserved fusion with the S1 domain-containing plastid-specific ribosomal protein-7
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DOI：
10.1105/tpc.104.026708
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发表时间：
2004-12-01
期刊：
影响因子：
11.6
通讯作者：
Mayfield, SP
中科院分区：
文献类型：
--
作者：
Beligni, MV;Yamaguchi, K;Mayfield, SP
叶绿体翻译的组分与原核生物翻译的组分相似，但包含一些额外的独特特征。对莱茵衣藻叶绿体核糖体的蛋白质组分析鉴定出一种类似S1的蛋白质，即质体特异性核糖体蛋白 - 7（PSRP - 7），它是30S亚基的化学计量组分。在此，我们报道PSRP - 7是一种多聚蛋白的一部分，该多聚蛋白在其氨基端包含PSRP - 7，在羧基端包含两个翻译延伸因子Ts（EF - Ts）结构域。我们将这种多聚蛋白命名为PETs（代表EF - Ts的多聚蛋白）。Pets是一个单拷贝基因，包含在莱茵衣藻基因组中发现的唯一的叶绿体PSRP - 7和EF - Ts序列。pets前体转录物经过可变剪接产生三种具有1.68、1.8和3kb开放阅读框（ORF）的mRNA。一种110 - kD的前体蛋白从3 - kb的ORF翻译而来，这种蛋白的大部分可能在翻译后被加工成65 - kD的蛋白质PSRP - 7和一种55 - kD的EF - Ts。在拟南芥和水稻（Oryza sativa）中发现了PETs的同源物。110 - kD的PETs多聚蛋白在植物界的保守性表明PSRP - 7和EF - Ts在叶绿体翻译的某些方面共同发挥作用，并且PETs前体蛋白作为一个整体可能具有一种新的功能。
The components of chloroplast translation are similar to those of prokaryotic translation but contain some additional unique features. Proteomic analysis of the Chlamydomonas reinhardtii chloroplast ribosome identified an S1-like protein, plastid-specific ribosomal protein-7 (PSRP-7), as a stoichiometric component of the 30S subunit. Here, we report that PSRP-7 is part of a polyprotein that contains PSRP-7 on its amino end and two translation elongation factor Ts (EF-Ts) domains at the carboxy end. We named this polyprotein PETs (for polyprotein of EF-Ts). Pets is a single-copy gene containing the only chloroplast PSRP-7 and EF-Ts sequences found in the C. reinhardtii genome. The pets precursor transcript undergoes alternative splicing to generate three mRNAs with open reading frames (ORFs) of 1.68, 1.8, and 3 kb. A 110-kD pro-protein is translated from the 3-kb ORF, and the majority of this protein is likely posttranslationally processed into the 65-kD protein PSRP-7 and a 55-kD EF-Ts. PETs homologs are found in Arabidopsis thaliana and rice (Oryza sativa). The conservation of the 110-kD PETs polyprotein in the plant kingdom suggests that PSRP-7 and EF-Ts function together in some aspects of chloroplast translation and that the PETs pro-protein may have a novel function as a whole.