Shafritz D A, Laycock D G, Anderson W F
Proc Natl Acad Sci U S A. 1971 Feb;68(2):496-9. doi: 10.1073/pnas.68.2.496.
The ability to form a "peptide" bond between various forms of Met-tRNA or Phe-tRNA and puromycin has been studied in the reticulocyte cell-free system. When Met-tRNA(F), fMet-tRNA(F), or N-acetylPhe-tRNA are used as substrate at low Mg(++) concentration (3 mM), reticulocyte initiation factors M(1) and M(2) (M(2A) + M(2B)) are required for puromycin-peptide synthesis. In contrast to bacterial systems, this reaction is also stimulated by the elongation factor T(1). When Met-tRNA(M) or Phe-tRNA is used as substrate, there is no M-factor requirement for the puromycin reaction; T(1) is absolutely required, and the reaction is stimulated by T(2). These studies indicate that reticulocyte factors M(1) and M(2) may function in part by placing the initiator tRNA into the P site. The detailed mechanism for mammalian initiation, however, may be more complex than that for bacterial systems.
在网织红细胞无细胞体系中,已经对各种形式的甲硫氨酰 - tRNA或苯丙氨酰 - tRNA与嘌呤霉素之间形成“肽”键的能力进行了研究。当在低镁离子浓度(3 mM)下使用甲硫氨酰 - tRNA(F)、甲酰甲硫氨酰 - tRNA(F)或N - 乙酰苯丙氨酰 - tRNA作为底物时,网织红细胞起始因子M(1)和M(2)(M(2A) + M(2B))参与嘌呤霉素 - 肽的合成。与细菌体系不同,该反应也受到延伸因子T(1)的刺激。当使用甲硫氨酰 - tRNA(M)或苯丙氨酰 - tRNA作为底物时,嘌呤霉素反应不需要M因子;绝对需要T(1),并且该反应受到T(2)的刺激。这些研究表明,网织红细胞因子M(1)和M(2)可能部分通过将起始tRNA放置到P位点起作用。然而,哺乳动物起始的详细机制可能比细菌体系更为复杂。