title: Discovery of potent CLC chloride channel inhibitors.
abstract: Anion-transport proteins are central to all of physiology, for processes ranging from regulating bone-density, muscle excitability, and blood pressure, to facilitating extreme-acid survival of pathogenic bacteria. 4,4-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) has been used as an anion-transport inhibitor for decades. In this study, we demonstrate that polythiourea products derived from DIDS hydrolysis inhibit three different CLC chloride-transport proteins, ClC-ec1, ClC-0, and ClC-Ka, more effectively than DIDS itself. The structures of the five major products were determined by NMR spectroscopy, mass spectrometry, and chemical synthesis. These compounds bind directly to the CLC proteins, as evidenced by the fact that inhibition of ClC-0 occurs only from the intracellular side and inhibition of ClC-Ka is prevented by the point mutation N68D. These polythioureas are the highest affinity inhibitors known for the CLCs and provide a new class of chemical probes for dissecting the molecular mechanisms of chloride transport.
authors.affiliation: Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Matulef
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Howery
authors.forename: Li
authors.initials: L
authors.lastname: Tan
authors.forename: William R
authors.initials: WR
authors.lastname: Kobertz
authors.forename: J
authors.initials: J
authors.lastname: Du Bois
authors.forename: Merritt
authors.initials: M
authors.lastname: Maduke
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000737:chemistry / Q000494:pharmacology; D000838:Anions / Q000378:metabolism; D018118:Chloride Channels / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D020650:Combinatorial Chemistry Techniques; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D015394:Molecular Structure; D013890:Thiourea / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000838:Anions; D018118:Chloride Channels; D002712:Chlorides; D013890:Thiourea; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid