What can we learn about a protein from NMR?
1) Solve a structure
The standard approach to NMR protein structure.
2) Details about protein motion, interactions, etc.
|Mapping interactions by chemical shift changes.||Mapping interactions by NOE (relaxation and dipolar coupling).|
|Residual dipolar coupling (RDC) for relative bond orientation. Great potential for structure work.||pH titrations (chemical shift).|
Rotational motion of side chains.
|Mobility of protein domains by relaxation. Difficult to interpret physically because of complexity of relaxation mechanisms.|
Let's say you have 3 mg of a 100-residue protein, in 0.3 ml of buffer...
1D spectrum of a small protein
2D NOESY spectrum of a protein
Works well for ~ 100 amino acids, but starts to look hairy for larger proteins...