Protein structural motif recognition via NMR residual dipolar couplings

NMR residual dipolar couplings have great potential to provide rapid struct ural information for proteins in the solution state. This information even at low resolution may be used to advantage in proteomics projects that seek to annotate large numbers of gene products for entire genomes. In this pap er, we describe a novel approach to the structural interpretation of dipola r couplings which is based on structural motif pattern recognition, where a predefined gapless structural template for a motif is used to search a set of residual dipolar couplings for good matches. We demonstrate the applica bility of the method using synthetic and experimental data. We also provide an analysis of the statistical power of the method and the effects of orde r tensor frame orientation, motif size, and structural complexity on motif detection. Finally, we discuss remaining problems that must be overcome bef ore the method can be used routinely to identify protein homologies.