Two methods are currently available to solve high resolution protein
structures-X-ray crystallography and nuclear magnetic resonance (NMR). Both
methods usually produce highly similar structures, but small differences between
both solutions are always observed. Here the raw NMR data as well as the solved
NMR structure were compared to the multiple crystal structures solved for the WT
60 residue three helix bundle engrailed homeodomain (EnHD) and single point
mutants. There was excellent agreement between TALOS-predicted and crystal
structure-observed dihedral angles and a good agreement for the (3) J(H ( N ) H
( alpha )) couplings for the multiple crystal structures. Around 1% of NOEs were
violated for any crystal structure, but no NOE was inconsistent with all of the
crystal structures. Violations usually occurred for surface residues or for
residues for which multiple discreet conformations were observed between the
crystal structures. Comparison of the disorder shown in the multiple crystal
structures shows little correlation with dynamics under native conditions for
this protein.
