POLYAMINE INDUCED Z-CONFORMATION OF NATIVE CALF THYMUS DNA

Conformational isomerization of native calf thymus DNA under the influ ence of spermine, spermidine and putrescine was monitored by UV absorp tion and immunospecific anti-Z-DNA antibodies, Immunological data indi cated increased binding of anti-Z-DNA antibodies to polyamine-perturbe d conformations of native DNA and double stranded poly(dG-dC), In the absence of polyamines, anti-Z-DNA antibodies did not bind to either po lymers, Analysis of UV absorption studies indicates a left handed conf ormation of nDNA in the presence of polyamines. Moreover, we observed total aggregation of DNA in the presence of spermine on prolongued inc ubation, These perturbations in conformation were dependent on polyami ne concentration. The results clearly suggest that certain regions of nDNA are sensitive to elevated levels of polyamines and are capable of undergoing B --> Z transition.