Simultaneous stability of short alternating Z and B helices in synthetic DNA concatamers.

The conformation of d(TA)3 (CG)3 has been studied in aqueous solution in the presence of high salt concentration. The oligonucleotide forms in solution concatamers. In the presence of 5 M NaC1 the concatamer is built up of d(CG)3 blocks in Z-conformation and of d(TA)3 blocks in B-conformation. In the presence of 4 M LiCl both blocks in the concatamer display a B-type structure.