RNAのリン酸化酵素としてClp1が知られている。Clp1の大規模分子進化解析の結果、計3,577件のClp1関連タンパク質を検出した。その多くは真核生物やアーキアに由来し、バクテリアには限られた種にしか存在しなかった。Clp1のキナーゼドメインは、全てのClp1関連タンパク質に共通であり、N末端やC末端領域には生物種やファミリーに特徴的なドメインが保存されていた。また、1,000アミノ酸残基以上の巨大なClp1関連タンパク質を122個検出した。さらに、Thermus scotoductus Clp1組換え体酵素を用いて、バクテリアClp1のリン酸化活性を世界で初めて実験科学的に検証した。
We conducted a large-scale molecular evolutionary analysis of the Clp1 family proteins, a polyribonucleotide 5'-hydroxyl kinases. In total, 3,557 Clp1 family proteins were detected in the three domains of life, Bacteria, Archaea, and Eukarya. Many were from Archaea and Eukarya, but a few were found in restricted, phylogenetically diverse bacterial species. The domain structures of the Clp1 family proteins also differed among the three domains of life. Although the proteins were, on average, 555 amino acids long (range, 196-2,728), 122 large proteins with > 1,000 amino acids were detected in eukaryotes. The polyribonucleotide kinase activity of Thermus scotoductus Clp1 was characterized experimentally. We propose a comprehensive assessment of the diversification of the Clp1 family proteins and the molecular evolution of their functional domains.
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