PREDICTION OF THE STABILITY OF DNA TRIPLEXES

摘要: Abstract We present rules that allow one to predict the stability of DNA pyrimidine.purine.pyrimidine (Y.R.Y) triple helices on basis sequence. The were derived from van't Hoff analysis 23 oligonucleotide triplexes tested at a variety pH values. To enthalpy triplex formation (delta H degrees), simple nearest-neighbor model was found be sufficient. However, accurately free energy G combination consisting five parameters needed. These (i) delta degrees for helix initiation, (ii) adding T-A.T triple, (iii) C(+)-G.C (iv) penalty adjacent C bases, and (v) dependence triple's stability. fitted are highly consistent with thermodynamic data set, generally predicting both within experimental error. Examination points out several interesting features. predicts C(+) -G.C. triples much more stabilizing than below 7.0 former increases approximately equal 1 kcal/mol per unit as is decreased. Surprisingly though, most stable sequence predicted CT repeat, bases partially cancel another. successfully tm values other laboratories, some exceptions.