アミノアシルtRNA合成反応における二価陽イオンとポリアミンの役割

概要

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Requirement of Mg2+ in aminoacyl-tRNA formation has been well established. Replacement of Mg2+ requirement by various cations, such as Mn2+, Ca2+, Co2+, K+ and NH+4 has also been reported. Polyamines, such as spermine, spermidine and putrescine, could also replace Mg2+ requirement in several aminoacyl-tRNA formations. The role of these cations in the reaction was studied and it was found that these cations played two distinct roles; that is, (1) to bind to tRNA to activate it to be charged with amino acids, (2) to bind tightly to aminoacyl-tRNA synthetase, probably at its active center, which is necessary for the enzyme to be active. Mg2+ could play both the role (1) and (2), whereas polyamines could play the role (1). Mn2+ seemed to be very important to play the role (2). Concerted mechanism of aminoacyl-tRNA formation in the presence of polyamines is also discussed.
日本生物物理学会の論文