The conformation of an inhibitor bound to the gastric proton pump.

Journal article

Substituted imidazo[1,2-a]pyridines are pharmaceutically important small molecule inhibitors of the gastric H+/K+-ATPase, the membrane-bound therapeutic target for peptic ulcer disease. A non-perturbing analytical technique, rotational resonance NMR spectroscopy, was used to measure a precise (to +/-0.2 A) distance between atomic sites in a substituted imidazo[1,2-a]pyridine, TMPIP, bound to H+/K+-ATPase at its high-affinity site in the intact, native membrane. The structural analysis of the enzyme-inhibitor complex revealed that the flexible moiety of TMPIP adopts a 'syn-type' conformation at its site of action. Hence, the conformation of an inhibitor has been resolved directly under near-physiological conditions, providing a sound experimental basis for rational design of many active compounds of pharmaceutical interest. Chemically restraining the flexible moiety of compounds like TMPIP in the syn-type binding conformation was found to increase activity by over 2 orders of magnitude. Such information is normally only available after extensive synthesis of related compounds and multiple screening approaches.

Authors: Middleton, D; Robins, R; Feng, X; Levitt, M; Spiers, I

• Publication status: Published
• Journal: FEBS letters
• Volume: 410
• Issue: 2-3
• Pages: 269-274
• Publication date: 1997-06-01
• DOI: 10.1016/s0014-5793(97)00525-5
• EISSN: 1873-3468
• ISSN: 0014-5793
• Language: English
• Keywords: Molecular Structure; H(+)-K(+)-Exchanging ATPase; Stomach; Magnetic Resonance Spectroscopy; Proton Pumps; Pyridines