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：1986
卷号：83
期号：5
页码：1189-1192
DOI：10.1073/pnas.83.5.1189
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The tyrosyl-tRNA synthetase (EC 6.1.1.1 ) from Bacillus stearothermophilus is a dimer of two identical subunits. The dimer shows "half-of-the-sites" reactivity in that only one molecule of tyrosyladenylate is formed and one molecule of tRNATyr binds per dimer. To identify whether the tRNATyr binds to a single subunit in the dimer, or to both subunits, heterodimers were constructed by mixing two variant dimers together in 8 M urea. As the unfolded protein is electrophoresed into a native polyacrylamide gel, it refolds and reassociates, and heterodimers can be purified from the parental dimers. Kinetic analysis of heterodimers formed between variant enzymes with defective tyrosine activation or tRNA aminoacylation shows that a molecule of tRNATyr interacts with the N-terminal region of one subunit and the C-terminal region of the other subunit in the dimer.
