Carbonic anhydrase inhibitors: binding of an antiglaucoma glycosyl-sulfanilamide derivative to human isoform II and its consequences for the drug design of enzyme inhibitors incorporating sugar moieties.
N-(4-Sulfamoylphenyl)-alpha-d-glucopyranosylamine, a promising topical antiglaucoma agent, is a potent inhibitor of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The high resolution X-ray crystal structure of its adduct with the target isoform involved in glaucoma, CA II, is reported here. The sugar sulfanilamide derivative binds to the enzyme in a totally new manner as compared to other CA-inhibitor adducts investigated earlier. The sulfonamide anchor was coordinated to the active site metal ion, and the phenylene ring of the inhibitor filled the channel leading to the active site cavity. The glycosyl moiety responsible for the high water solubility of the compound was oriented towards a hydrophilic region of the active site, where no other inhibitors were observed to be bound up to now. A network of seven hydrogen bonds with four water molecules and the amino acid residues Pro201, Pro202 and Gln92 further stabilize the enzyme-inhibitor adduct. Topiramate, another sugar-based CA inhibitor, binds in a completely different manner to CA II as compared to the sulfonamide investigated here. These findings are useful for the design of potent, sugar-derived enzyme inhibitors.
Di Fiore
Anna
A
Istituto di Biostrutture e Bioimmagini-CNR, via Mezzocannone 16, 80134 Naples, Italy.
Scozzafava
Andrea
A
Winum
Jean-Yves
JY
Montero
Jean-Louis
JL
Pedone
Carlo
C
Supuran
Claudiu T
CT
De Simone
Giuseppina
G
D001665:Binding Sites; D002241:Carbohydrates / Q000737:chemistry / Q000494:pharmacology; D024402:Carbonic Anhydrase II / Q000378:metabolism*; D002257:Carbonic Anhydrase Inhibitors / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D015195:Drug Design; D005632:Fructose / Q000031:analogs & derivatives / Q000494:pharmacology; D005901:Glaucoma / Q000188:drug therapy*; D006801:Humans; D006860:Hydrogen Bonding; D007527:Isoenzymes / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D013424:Sulfanilamides / Q000138:chemical synthesis* / Q000494:pharmacology*; D000077236:Topiramate
D002241:Carbohydrates; D002257:Carbonic Anhydrase Inhibitors; D007527:Isoenzymes; D013424:Sulfanilamides; D000077236:Topiramate; D005632:Fructose; D024402:Carbonic Anhydrase II