Nuclear magnetic resonance structure-based drug design

NMR Molecular Replacement Provides New Insights into Binding Modes to Bromodomains of BRD4 and TRIM24

Structure-based drug discovery (SBDD) largely relies on structural information from X-ray crystallography because traditional NMR structure calculation methods are too time consuming to be aligned with typical drug discovery timelines. The recently developed NMR molecular replacement (NMR²) method dramatically reduces the time needed to generate ligand-protein complex structures using published structures (apo or holo) of the target protein and treating all observed NOEs as ambiguous restraints, bypassing the laborious process of obtaining sequence-specific resonance assignments for the protein target. We apply this method to two therapeutic targets, the bromodomain of TRIM24 and the second bromodomain of BRD4. We show that the NMR² methodology can guide SBDD by rationalizing the observed SAR. We also demonstrate that new types of restraints and selective methyl labeling have the potential to dramatically reduce "time to structure" and extend the method to targets beyond the reach of traditional NMR structure elucidation.

Protein-ligand structure determination with the NMR molecular replacement tool, NMR2

We recently reported on a new method called NMR Molecular Replacement that efficiently derives the structure of a protein-ligand complex at the interaction site. The method was successfully applied to high and low affinity complexes covering ligands from peptides to small molecules. The algorithm used in the NMR Molecular Replacement program has until now not been described in detail. Here, we present a complete description of the NMR Molecular Replacement implementation as well as several new features that further reduce the time required for structure elucidation.

Protein-fragment complex structures derived by NMR molecular replacement

Recently we have established an NMR molecular replacement method, which is capable of solving the structure of the interaction site of protein-ligand complexes in a fully automated manner. While the method was successfully applied for ligands with strong and weak binding affinities, including small molecules and peptides, its applicability on ligand fragments remains to be shown. Structures of fragment-protein complexes are more challenging for the method since fragments contain only few protons. Here we show a successful application of the NMR molecular replacement method in solving structures of complexes between three derivatives of a ligand fragment and the protein receptor PIN1. We anticipate that this approach will find a broad application in fragment-based lead discovery.