Kubarenko A V, Sergiev P V, Rodnina M V
Mol Biol (Mosk). 2005 Sep-Oct;39(5):746-61.
Protein biosynthesis is a complex biochemical process. It integrates multiple steps where different translation factors specifically interact with the ribosome in a precisely defined order. Among the translation factors one can find multiple GTP-binding or G-proteins. Their functioning is accompanied by GTP hydrolysis to the GDP and inorganic phosphate ion Pi. Ribosome stimulates the GTPase activity of the translation factors, thus playing a role analogues to GTPase-activating proteins (GAP). Translation factors--GTPases interact with the ribosome at all stages of protein biosynthesis. Initiation factor 2 (IF2) catalyse initiator tRNA binding to the ribosomal P-site and subsequent subunit joining. Elongation factor Tu (EF-Tu) is responsible for the aminoacyl-tRNA binding to the ribosomal A-site, while elongation factor G (EF-G) catalyses translocation of mRNA in the ribosome by one codon, accompanied by tRNA movement between the binding sites. In its turn, release factor 3 (RF3) catalyse dissociation of the ribosomal complex with release factors 1 or 2 (RF1 or RF2) following the peptide release. This review is devoted to the functional peculiarities of translational GTPases as related to other G-proteins. Particularly, to the putative GTPase activation mechanism, structure and functional cycles.
蛋白质生物合成是一个复杂的生化过程。它整合了多个步骤，其中不同的翻译因子以精确确定的顺序与核糖体特异性相互作用。在翻译因子中可以发现多种GTP结合蛋白或G蛋白。它们的功能伴随着GTP水解为GDP和无机磷酸离子Pi。核糖体刺激翻译因子的GTPase活性，从而发挥类似于GTPase激活蛋白（GAP）的作用。翻译因子——GTPases在蛋白质生物合成的所有阶段都与核糖体相互作用。起始因子2（IF2）催化起始tRNA与核糖体P位点结合以及随后的亚基结合。延伸因子Tu（EF-Tu）负责氨酰-tRNA与核糖体A位点的结合，而延伸因子G（EF-G）催化核糖体中mRNA移动一个密码子，同时tRNA在结合位点之间移动。反过来，释放因子3（RF3）在肽释放后催化核糖体复合物与释放因子1或2（RF1或RF2）解离。本综述致力于翻译GTPases与其他G蛋白相关的功能特性。特别是，探讨假定的GTPase激活机制、结构和功能循环。
