SmartSci is a small company that offers consultancy and develops scientific software in Cambridge. A particular focus is in the refinement of X‑ray structures of protein‑ligand complexes to achieve high quality ligand chemistry.
The BUSTER re-refinement of 4BKI using a Grade dictionary (left). The difference electron density (green) and consideration of ligand strain show that indolin-2-one ring of kinase inhibitor DDR1-IN-1 has been placed the wrong way around. The ligand placement after a ring flip and re-refinement is good (right), with a good fit to the 2Fo-Fc density (cyan). After seeing this analysis, Canning, Bullock and co-workers have deposited a corrected structure 4CKR. The correction has implications for using structure-guided drug design [Kim et al., 2014]. Pictures produced using Coot and used by kind permission of Global Phasing Ltd.