In article <2m3heg$d4e at usenet.INS.CWRU.Edu> Dan Diaz, bl275 at cleveland.Freenet.Edu writes: >Use of dATP(alpha-S) leads to the formation of phosphorothioates, whose >structure is: > S > 5'-dN~ O P O ~dA-3' > O > >which is still a (thio)phosphate diester and not thermolabile, as are sulfate >diesters. Ahhh! The light dawns. Thanks, Diz Good luck, Jim Owens