Computer analyses of complete genomes suggest that some archaebacteria employ both eukaryotic and eubacterial mechanisms in translation initiation.
Computer analyses of complete genomes suggest that some archaebacteria employ both eukaryotic and eubacterial mechanisms in translation initiation.
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对完整基因组的计算机分析表明，一些古细菌在翻译起始中同时采用真核和真细菌机制。
DOI：
10.1016/s0378-1119(99)00254-1
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发表时间：
1999
期刊：
影响因子：
3.5
通讯作者：
M. Tomita
中科院分区：
文献类型：
--
作者：
R. Saito;M. Tomita
古细菌的翻译起始机制至今仍不清楚。我们的前期工作表明，真核生物基因组中起始密码子前的ATG三联体已被强烈地耗尽，这可能是因为真核生物的核糖体从5′到3′方向扫描mRNA以找到合适的起始密码子。在起始密码子之前的额外的ATG三联体会混淆该过程，因此它们在真核基因组中被负选择。另一方面，在真细菌基因组中，核糖体在没有mRNA扫描的情况下立即结合到Shine-Dalgarno（SD）序列，并且没有观察到ATG三联体消耗的特征模式（Saito，R.，Tomita，M.，1999.真核生物和原核生物基因组中起始密码子附近的ATG三联体的负选择。J. Mol. Evol 48，213-217）。对古细菌基因组的ATG三联体分析表明，詹氏甲烷球菌和堀越火球菌的基因组结构与真核生物相似，表明它们在翻译起始过程中采用了从5′到3′方向的mRNA扫描。另一方面，我们早期的研究发现，这些古细菌具有SD样序列，其与16 S rRNA的3′端序列互补，如在真细菌翻译起始中那样（Osada，Y.，斋藤河，巴西-地富田，M。不同原核生物中16 S rRNA和5′ UTR之间翻译起始的碱基配对潜力分析Bioinformatics，in press）.这两个结果结合起来使我们得出结论，这些古生菌可能使用杂交机制，它们的核糖体从5′到3′方向扫描mRNA，然后16 S rRNA结合到5′ UTR的SD样序列。
The translation initiation mechanism of archaebacteria is still not clearly understood. Our previous work showed that ATG triplets before start codons have been strongly depleted in eukaryotic genomes, presumably because ribosome of eukaryotes scans mRNA from the 5′ to 3′ direction to find proper start codons. Extra ATG triplets before start codons would confuse the process and thus they have been negatively selected in eukaryotic genomes. In eubacterial genomes, on the other hand, ribosome binds to the Shine–Dalgarno (SD) sequence at once without mRNA scanning, and the characteristic patterns of ATG triplet depletion were not observed (Saito, R., Tomita, M., 1999. On negative selection against ATG triplets near start codons in eukaryotic and procaryotic genomes. J. Mol. Evol. 48, 213–217). The ATG triplet analysis on archaebacterial genomes revealed that Methanococcus jannaschii and Pyrococcus horikoshii show patterns similar to eukaryotes, implying that these species employ scanning of mRNA from the 5′ to 3′ direction in the process of translation initiation. On the other hand, our earlier study found that these archaea have SD-like sequences, which are complementary to the 3′ end sequence of 16S rRNA, as in eubacterial translation initiation (Osada, Y., Saito, R., Tomita, M. Analysis of base-pairing potentials between 16S rRNA and 5′ UTR for translation initiation in various procaryotes. Bioinformatics, in press). These two results combined lead us to conclude that these archaea probably use a hybrid mechanism; their ribosome scans mRNAs from the 5′ to 3′ direction and then 16S rRNA binds to the SD-like sequence of the 5′ UTR.
DOI：
10.1073/pnas.92.7.2662
发表时间：
1995-03-28
影响因子：
11.1
作者：
KOZAK, M
通讯作者：
KOZAK, M