On 04/15/2011 06:36 AM, bharat lal wrote: > I want to know whether long loop modeling of 30 or 40 residue length is > possible through modeller or not ??..

There's no theoretical upper bound on the loop length, but the conformational space that needs to be explored becomes extremely large very quickly. In practice we find that ~15 residues is about the limit - you'd have to do a lot of sampling to study loops of 30 residues.

Ben Webb, Modeller Caretaker