[phenixbb] Restraints for keeping base-pairs co-planar in RNA/DNA

Hi everybody: What would be proper approach to generate restraints that will keep base pairs coplanar (or nearly coplanar) in RNA/DNA helical structures? Hydrogen bonds by themselves are not sufficient, at least not for low resolution refinement, <4Å Jens *+++++++++++++++++++++++++++++++++++++++++++++++++++++++* * * *Jens J. Birktoft e-mail: [email protected] slow-mail: Dept. Chemistry, NYU, 350 CPW , Suite 9F, New York, NY 10025 Phone: 212-749-5057 *