Molecular signatures in protein sequences that are characteristic of cyanobacteria and plastid homologues
Molecular signatures in protein sequences that are characteristic of cyanobacteria and plastid homologues
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DOI：
10.1099/ijs.0.02720-0
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发表时间：
2003-11-01
影响因子：
2.8
通讯作者：
Johari, V
中科院分区：
文献类型：
--
作者：
Gupta, RS;Mark, PI;Johari, V
在10种广泛分布的蛋白质中发现了14种保守的插入/缺失（即插入或缺失），这些蛋白质似乎是蓝藻物种的特征，并且在任何其他细菌中都没有发现。这些签名包括6、7和28 aa的三个插入物。在DNA解旋酶II（UvrD）蛋白中，在DNA聚合酶I中的18-21个氨基酸插入，在酶ADP-葡萄糖焦磷酸化酶中的14个氨基酸插入，在FtsH蛋白中的3个氨基酸插入，在八氢番茄红素合酶中的11-13个氨基酸插入，在延伸因子-Tu中的5个氨基酸插入，在核糖体S1蛋白中的2和7个氨基酸的两个缺失，在SecA蛋白中的2个氨基酸插入，在肌苷-5 ′-单磷酸脱氢酶中有1个氨基酸缺失和6个氨基酸插入，在主要σ因子中有1个氨基酸缺失。这些签名，这是两侧的保守区域，提供区分蓝藻类群从所有其他细菌的分子标记，他们应该证明有助于蓝藻物种的鉴定，简单的基础上，这些标记的存在或不存在的相应的蛋白质。这些蛋白质（SecA，延伸因子-Tu，ADP-葡萄糖焦磷酸化酶，八氢番茄红素合成酶，FtsH和核糖体S1蛋白）中的六个签名也通常存在于植物和藻类（绿藻，有色植物和红藻）的质体同源物中，表明它们与蓝藻的特定关系，并支持它们从这些细菌的内共生起源。在系统发育树的基础上的一些这些蛋白质（SecA，UvrD，DNA聚合酶I，延伸因子-Tu）进行了研究，可用的蓝藻同源物分组在一起具有高亲和力（> 95%的自举值），支持的观点，蓝藻门是单系的，并确定的签名被引入到一个共同的祖先这个群体。
Fourteen conserved indels (i.e. inserts or deletions) have been identified in 10 widely distributed proteins that appear to be characteristic of cyanobacterial species and are not found in any other group of bacteria. These signatures include three inserts of 6, 7 and 28 aa. in the DNA helicase II (UvrD) protein, an 18-21 aa insert in DNA polymerase I, a 14 aa insert in the enzyme ADP-glucose pyrophosphorylase, a 3 aa insert in the FtsH protein, an 11-13 aa insert in phytoene synthase, a 5 aa insert in elongation factor-Tu, two deletions of 2 and 7 aa in ribosomal S1 protein, a 2 aa insert in the SecA protein, a 1 aa deletion and a 6 aa insert in the enzyme inosine-5'-monophosphate dehydrogenase and a 1 aa deletion in the major sigma factor. These signatures, which are flanked by conserved regions, provide molecular markers for distinguishing cyanobacterial taxa from all other bacteria and they should prove helpful in the identification of cyanobacterial species, simply on the basis of the presence or absence of these markers in the corresponding proteins. The signatures in six of these proteins (SecA, elongation factor-Tu, ADP-glucose pyrophosphorylase, phytoene synthase, FtsH and ribosomal S1 protein) are also commonly present in plastid homologues from plants and algae (chlorophytes, chromophytes and rhodophytes), indicating their specific relationship to cyanobacteria and supporting their endosymbicitic origin from these bacteria. In phylogenetic trees based on a number of these proteins (SecA, UvrD, DNA polymerase I, elongation factor-Tu) that were investigated, the available cyanobacterial homologues grouped together with high affinity (> 95% bootstrap value), supporting the view that the cyanobacterial phylum is monophyletic and that the identified signatures were introduced in a common ancestor of this group.