Small molecule conformation in the receptor‐bound state by the two‐dimensional spin exchange experiment

Abstract

Abstract Pure absorption phase two‐dimensional nuclear Overhauser spectrocopy (NOESY), using a short cycle time protocol, has been used to study cross‐relaxation between protons of ligands bound to proteins. The 2D experiment is an accurate and efficient method for determining exchange transferred NOEs. Truncated NOESY data sets (obtained in less than 3 h) for the test systems—prostaglandin F 2 α bound to albumin and NAD + bound to three different dehydrogenase enzymes—provide NOE estimates within experimental error of those obtained by the more time‐consuming one‐dimensional experiments. The 2D data matrix has within it spin‐diffusion controls and cross‐relaxation spectra useful for the subtraction of unwanted signals including spin transfer from coincidentally perturbed protein resonances and t 1 streaks and ridges.