[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.
[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.
Structure for the adduct of carbonic anhydrase II with 1-N-(4-sulfamoylphenyl-ethyl)-2,4,6-trimethylpyridinium perchlorate, a membrane-impermeant antitumor sulfonamide, is reported. The phenylethyl moiety fills the active site, making van der Waals interactions with side chains of Gln192, Val121, Phe131, Leu198, Thr200. The 2,4,6-trimethylpyridinium functionality is at van der Waals distance from the aliphatic chain of Ile91 being involved in strong offset face-to-face stacking with Phe131. Analyzing X-ray crystal structures of such adducts, two binding modes were observed: some inhibitors bind with their tail within the hydrophobic half of the active site, defined by residues Phe131, Val135, Leu198, Pro202, Leu204. Other derivatives bind with their tail in a different region, pointing toward the hydrophilic half and making strong parallel stacking with Phe131. This interaction orients the inhibitor toward the hydrophilic part of the active site. Impossibility to participate in it leads to its binding within the hydrophobic half. Such findings are relevant for designing better inhibitors targeting isozymes II, IX, and XII, some of which are overexpressed in hypoxic tumors.
Carbonic anhydrase inhibitors: stacking with Phe131 determines active site binding region of inhibitors as exemplified by the X-ray crystal structure of a membrane-impermeant antitumor sulfonamide complexed with isozyme II.,Menchise V, De Simone G, Alterio V, Di Fiore A, Pedone C, Scozzafava A, Supuran CT J Med Chem. 2005 Sep 8;48(18):5721-7. PMID:16134940
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
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↑ Roth DE, Venta PJ, Tashian RE, Sly WS. Molecular basis of human carbonic anhydrase II deficiency. Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1804-8. PMID:1542674
↑ Soda H, Yukizane S, Yoshida I, Koga Y, Aramaki S, Kato H. A point mutation in exon 3 (His 107-->Tyr) in two unrelated Japanese patients with carbonic anhydrase II deficiency with central nervous system involvement. Hum Genet. 1996 Apr;97(4):435-7. PMID:8834238
↑ Shah GN, Bonapace G, Hu PY, Strisciuglio P, Sly WS. Carbonic anhydrase II deficiency syndrome (osteopetrosis with renal tubular acidosis and brain calcification): novel mutations in CA2 identified by direct sequencing expand the opportunity for genotype-phenotype correlation. Hum Mutat. 2004 Sep;24(3):272. PMID:15300855 doi:10.1002/humu.9266
↑ Briganti F, Mangani S, Scozzafava A, Vernaglione G, Supuran CT. Carbonic anhydrase catalyzes cyanamide hydration to urea: is it mimicking the physiological reaction? J Biol Inorg Chem. 1999 Oct;4(5):528-36. PMID:10550681
↑ Kim CY, Whittington DA, Chang JS, Liao J, May JA, Christianson DW. Structural aspects of isozyme selectivity in the binding of inhibitors to carbonic anhydrases II and IV. J Med Chem. 2002 Feb 14;45(4):888-93. PMID:11831900
↑ Menchise V, De Simone G, Alterio V, Di Fiore A, Pedone C, Scozzafava A, Supuran CT. Carbonic anhydrase inhibitors: stacking with Phe131 determines active site binding region of inhibitors as exemplified by the X-ray crystal structure of a membrane-impermeant antitumor sulfonamide complexed with isozyme II. J Med Chem. 2005 Sep 8;48(18):5721-7. PMID:16134940 doi:http://dx.doi.org/10.1021/jm050333c