A DnaB intein in Rhodothermus marinus: Indication of recent intein homing across remotely related organisms
A DnaB intein in Rhodothermus marinus: Indication of recent intein homing across remotely related organisms
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DOI：
10.1073/pnas.94.15.7851
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发表时间：
1997-07-22
影响因子：
11.1
通讯作者：
Hu, ZM
中科院分区：
文献类型：
--
作者：
Liu, XQ;Hu, ZM
编码大肠杆菌 DNA 解旋酶 DnaB 同源物的 dnaB 基因在嗜热真细菌红嗜热菌 (Rhodothermus marinus) 中进行了克隆和测序，预测了含有内含肽的 DnaB 蛋白。该 DnaB 内含肽长 428 个氨基酸残基，具有多个推定的内含肽序列基序（包括两个推定的核酸内切酶基序），并且在大肠杆菌细胞中产生时能够进行蛋白质剪接。 R. marinus DnaB 内含肽是蓝藻集胞藻属 DnaB 内含肽的密切同源物。菌株PCC6803。两个内含肽在各自的 DnaB 蛋白中位置相同。它们还具有 54% 的序列同一性（74% 序列相似性），明显高于两种 DnaB 蛋白的外显肽序列所共有的 37% 序列同一性。因此，水平内含肽转移（归巢）被用来关联这两个 DnaB 内含肽。 R. marinus DnaB 内含肽编码序列的密码子使用与其侧翼外显蛋白编码序列和同一基因组中的其他基因的密码子使用显着不同，表明该生物体中 DnaB 内含肽是最近获得的。
A dnaB gene encoding a homologue of the Escherichia coli DNA helicase DnaB was cloned and sequenced in the thermophilic eubacterium Rhodothermus marinus, predicting a DnaB protein that harbors an intein. This DnaB intein is 428 amino acid residues long, has several putative intein sequence motifs (including two putative endonuclease motifs), and is capable of protein splicing when produced in E. coli cells. The R. marinus DnaB intein is a close homologue of a DnaB intein in the cyanobacterium Synechocystis sp. strain PCC6803. The two inteins are positioned identically in their respective DnaB proteins. They also share a 54% sequence identity (74% sequence similarity) that is markedly higher than the 37% sequence identity shared by the extein sequences of the two DnaB proteins. Horizontal intein transfer (homing) is therefore invoked to relate these two DnaB inteins. The codon usage of R. marinus DnaB intein coding sequence differs markedly from the codon usages of its flanking extein coding sequences and other genes in the same genome, suggesting more recent acquisition of the DnaB intein in this organism.