4bf1 | pdb_00004bf1
Three dimensional structure of human carbonic anhydrase II in complex with 5-(1-naphthalen-1-yl-1,2,3-triazol-4-yl)thiophene-2-sulfonamide
Structural highlights
Disease[CAH2_HUMAN] Defects in CA2 are the cause of osteopetrosis autosomal recessive type 3 (OPTB3) [MIM:259730]; also known as osteopetrosis with renal tubular acidosis, carbonic anhydrase II deficiency syndrome, Guibaud-Vainsel syndrome or marble brain disease. Osteopetrosis is a rare genetic disease characterized by abnormally dense bone, due to defective resorption of immature bone. The disorder occurs in two forms: a severe autosomal recessive form occurring in utero, infancy, or childhood, and a benign autosomal dominant form occurring in adolescence or adulthood. Autosomal recessive osteopetrosis is usually associated with normal or elevated amount of non-functional osteoclasts. OPTB3 is associated with renal tubular acidosis, cerebral calcification (marble brain disease) and in some cases with mental retardation.[1] [2] [3] [4] [5] Function[CAH2_HUMAN] Essential for bone resorption and osteoclast differentiation (By similarity). Reversible hydration of carbon dioxide. Can hydrate cyanamide to urea. Involved in the regulation of fluid secretion into the anterior chamber of the eye.[6] [7] Publication Abstract from PubMedWe report here a series of 2-thiophene-sulfonamides incorporating 1-substituted aryl-1,2,3-triazolyl moieties, prepared by click chemistry from 5-ethynylthiophene-2-sulfonamide and substituted aryl azides. The new sulfonamides were investigated as inhibitors of the zinc metalloenzyme CA (EC 4.2.1.1), and more specifically against the human (h) cytosolic isoforms hCA I and II and the transmembrane, tumor-associated ones hCA IX and XII: The new compounds were medium-weak hCA I inhibitors (KIs in the range of 224-7544nM), but were compactly, highly effective, low nanomolar hCA II inhibitors (KIs of 2.2-7.7nM). The tumor-associated hCA IX was inhibited with KIs ranging between 5.4 and 811nM, whereas hCA XII with inhibition constants in the range of 3.4-239nM. The X-ray crystal structure of the adducts of two such compounds bound to hCA II (one incorporating 1-naphthyl, the other one 3-cyanophenyl moieties) evidenced the reasons of the high affinity for hCA II. Highly favorable, predominantly hydrophobic interactions between the sulfonamide scaffold and the hCA II active site were responsible for the binding, in addition to the coordination of the sulfamoyl moiety to the zinc ion. The tails of the two inhibitors adopted very diverse orientations when bound to the active site, with the naphthyltriazolyl moiety orientated towards the hydrophobic half of the active site, and the 3-cyanophenyl one pointing towards the hydrophilic half. These data may be used for the structure-based drug design of even more effective hCA II inhibitors, with potential use as antiglaucoma agents or as diuretics. 5-Substituted-(1,2,3-triazol-4-yl)thiophene-2-sulfonamides strongly inhibit human carbonic anhydrases I, II, IX and XII: solution and X-ray crystallographic studies.,Leitans J, Sprudza A, Tanc M, Vozny I, Zalubovskis R, Tars K, Supuran CT Bioorg Med Chem. 2013 Sep 1;21(17):5130-8. doi: 10.1016/j.bmc.2013.06.041. Epub, 2013 Jun 27. PMID:23859774[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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