Intermolecular interactions and water structure in a condensed phase B-DNA crystal

Abstract

By controlled dehydration, the unit cells of dodecamer DNA-drug crystals have been shrunk from 68,000 (normal state) to 60,000 (partially dehydrated intermediate state) to 51,000 Å3 (fully dehydrated state), beyond which no further solvent loss occurs. The total solvent content in the normal crystals is ~ 40% by volume, reducing to ~ 20% in the fully dehydrated phase. The 25% reduction in cell volume induced a dramatic enhancement in the resolution of the X-ray diffraction data (from 2.6 to beyond 1.5 Å). We have determined the structures of the normal, partially dehydrated and fully dehydrated crystals. Details of the ligand binding have been presented in the preceding article. The present ..