I work with Dr. Ojha. We have AMBER4.0 at Gorakhpur University India. I have a problem in running amber. After dynamics of a dna molecule both strands are melted. One way is to put some distance constrain for the hydrogen bonds. Is there any direct methodwith out using constraints so that it should not melt. It is melting in both cases, in absence and presence of ions. If so please write me and oblige. Yours sinceerely R.K. Tiwari