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:1976
卷号:73
期号:9
页码:2987-2990
DOI:10.1073/pnas.73.9.2987
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The phosphodiester bond formation by DNA-dependent RNA-polymerase (RNA nucleotidyltransferase, nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6 ) can in principle result in retention, inversion, or racemization of configuration at the alpha-phosphorus of the nucleoside 5'-triphosphate being polymerized. As a first step in elucidating the stereochemistry of this reaction, one diastereomer (A) of adenosine 5'-O-(1-thiotriphosphate) (ATPalphaS) was polymerized with UTP in the presence of poly(dA-dT)-poly(dA-dT). The resulting polymer was enzymatically cleaved to uridine 2',3'-cyclic phosphorothioate which was determined to be the endo-isomer by comparison with an authentic sample. This shows that no reacemization had occurred and that isomer A of ATPalphaS gives a phosphorothioate diester bond with the R-configuration. Whether this represents inversion of retention of configuration awaits elucidation of the absolute configuration of isomer A for ATPalphaS.