Change feature of torsion angles in conformation transition on DNA B to Z

The conformations, which might reflect B-->Z transition, were modeled by ch anging 8 torsion angles df 5'-deoxyguanylic acid (G) and were calculated by quantum chemistry method. The results showed that torsion angle gamma, who se change results in the energy feature as the 8 torsion angles change toge ther, is of crucial importance in the transition. The others could be divid ed into two groups: alpha, delta and beta, epsilon, chi, nu(0), nu(1). The former affects Z conformation emergence with going up of the total-molecula r energy. However, the latter makes little difference in the formation of n ew conformations due to the smooth energy curves.