Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Geometrical minimization for a group of POPU (A) and POPA (B) molecules performed with Hyperchem 5.1 using AMBER force field. The orientation of purinic rings is strongly altered by the interaction between bases, whereas the pyrimidinic bases keep, more or less, their original conformation.
