标题：Structure and function of peptide initiation factor 2: differential loss of activities during proteolysis and generation of a terminal fragment containing the phosphorylation sites of the alpha subunit
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：1982
卷号：79
期号：10
页码：3158-3161
DOI：10.1073/pnas.79.10.3158
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A procedure is described by which the 38,000-dalton alpha subunit of native eukaryotic peptide initiation factor 2 (eIF-2) can be cleaved by trypsin to yield a 34,000-dalton fragment and a peptide of about 4,000 daltons after elimination of the beta subunit. Under nondenaturing conditions the 4,000-dalton peptide remains bound to the modified eIF-2 and still can be phosphorylated by the heme-controlled eIF-2 alpha kinase from reticulocytes. All of the phosphorylation sites for this protein kinase are located on the 4,000-dalton peptide. The ability of eIF-2 to form a ternary complex with GTP and Met-tRNAf and the ability to promote binding of Met-tRNAf to 40S ribosomal subunits are lost differentially during the proteolysis. Loss of te latter activity occurs rapidly and appears to be correlated with loss of the beta subunit. Loss of activity for ternary complex formation is correlated with the appearance of the 4,000-dalton peptide.
