文章基本信息

标题：Reversal of Pactamycin Inhibition of Methionyl-Puromycin Synthesis and 80S Initiation Complex Formation by a Ribosomal Joining Factor
本地全文：下载
作者：Hideo Suzuki ; Irving H. Goldberg
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：10
页码：4259-4263
DOI：10.1073/pnas.71.10.4259
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A crude mixture of polypeptide chain initiation factors (0.5 M KCl ribosomal wash) from reticulocyte ribosomes was fractionated by DEAE-cellulose column chromatography. Among several initiation factors obtained from the column, one factor eluting at 0.22-0.25 M KCl showed a remarkable ability to overcome the inhibition of Met-puromycin and 80S initiation complex formation caused by the antibiotic, pactamycin. Earlier experiments had shown that pactamycin does not prevent the binding of Met-tRNAf to the small ribosomal subunit but does interfere with the joining of the 60S ribosomal subunit to form the 80S initiation complex. A Lineweaver-Burk plot of initial rates of Met-puromycin formation showed that the interaction of the factor and pactamycin was of a competitive type. In the absence of the factor, [35S]Met-puromycin was not synthesized and [35S]Met-tRNAf bound only to the small ribosomal subunit. The amount of [35S]Met-tRNAf bound to 80S ribosomes bearing endogenous mRNA and the amount of [35S]Met-puromycin formed were directly related to the amount of factor added. Thus, this factor can be termed a "joining factor," and a simple assay of its activity can be devised based on its ability to overcome the pactamycin inhibition of the puromycin reaction.
关键词：initiation factors ; Met-tRNA_f binding ; Lineweaver-Burk analysis ; reticulocytes