There are about 20 structures solved by NMR with chain lengths above 300 residues. Some of them are solved by combination of restraints and modeling (e.g. 2010 Nature paper describing implementation of Rosetta modeling coupled with backbone-only data, by Raman/Montelione/Baker et al.).
Principal problems from the perspective of a non-specialist are: a) separation between resonances - complete (multidimensional!) overlaps are ruinous for assignment b) intensity of each resonance - for larger molecules there is less moles of resonating nuclei c) relaxation issues in large proteins (the need for expensive and hard to do deuterium labeling is the result of this) I am sure that true NMR experts would have much more to say on the subject :) Artem On Thu, Jun 30, 2011 at 5:20 PM, Lena Griese <lena.gri...@googlemail.com>wrote: > Dear members, > > I know that it is not possible to solve a structure by nmr of more than > approx. 30 kda. But I have to admit that I dont know why. What exactly is > overlapping? > > With best regards, > Lena >
