Divergent Evolution of 5 S rRNA Genes in Methanococcus
Divergent Evolution of 5 S rRNA Genes in Methanococcus
复制标题
甲烷球菌中 5S rRNA 基因的趋异进化
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
A. Böck
中科院分区：
文献类型：
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作者：
G. Wich;L. Sibold;A. Böck
摘要 产甲烷古细菌 Methanococcus (M .) voltae 中 5S rRNA 基因的组织及其核苷酸序列已被确定。 M. voltae 拥有三个 5S rRNA 基因，其中之一组织在编码 16S-23S-5S rRNA 的 rRNA 转录单元中。另外两个与假定转录单元中的七个 tRNA 基因相关，该转录单元由 5'-tRNAThr-tRNAPro-tRNATyr-tRNALys - 5S rRNA-tRNAAsp-tRNALys - 5S rRNA-tRNAAsp-3' 组成。该基因簇的 tRNALys-5S rRNA-tRNAAsp 块的编码区和间隔区以相同的序列出现两次。该簇中的 5S rRNA 显示出与 rRNA 操纵子连接的 5S rRNA 基因相当大的序列差异。将 M. voltae 5S rRNA 序列与来自 M. vannielii 的序列进行比较表明，一方面与操纵子连接的基因，另一方面与 tRNA 连接的 5S 基因比这两种生物体内的两种类型的基因具有更大的序列同源性。这表明两组 5S rRNA 基因的独立进化，没有来自其他核糖体成分的选择压力，或者横向基因转移。
Abstract The organization of genes for 5S rRNA in the methanogenic archaebacterium Methanococcus (M .) voltae and their nucleotide sequences have been determined. M. voltae possesses three 5S rRNA genes, one of them is organized in an rRNA transcriptional unit coding for 16S-23S-5S rRNA. The other two are associated with seven tRNA genes in a putative transcriptional unit composed of 5′-tRNAThr-tRNAPro-tRNATyr-tRNALys - 5S rRNA-tRNAAsp-tRNALys - 5S rRNA-tRNAAsp-3′. Coding regions plus spacers of the tRNALys-5S rRNA-tRNAAsp block of this gene cluster occur twice with identical sequence. The 5S rRNA from this cluster displays considerable sequence divergence to the rRNA operon-linked 5S rRNA gene. Comparison of the M. voltae 5S rRNA sequences with those from M. vannielii revealed that the operon-linked genes on one hand and the tRNA-linked 5S genes on the other share a greater sequence homology than the two types of genes within each of the two organisms. This indicates an independent evolution of the two sets of 5S rRNA genes without selective pressure from other ribosomal components or, alternatively, lateral gene transfer.