1okl
From Proteopedia
CARBONIC ANHYDRASE II COMPLEX WITH THE 1OKL INHIBITOR 5-DIMETHYLAMINO-NAPHTHALENE-1-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] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe three-dimensional structure of human carbonic anhydrase II (CAII) complexed with the sulfonamide fluorophore 5-dimethylamino-1-naphthalene sulfonamide (dansylamide) has been determined to 2.1-A resolution by x-ray crystallographic methods. Unlike other arylsulfonamide inhibitors of CAII, the naphthyl ring of dansylamide binds in a hydrophobic pocket in the active site, making van der Waals contacts with Val-121, Phe-131, Val-143, Leu-198, and Trp-209. Interestingly, a conformational change of Leu-198 is required to accommodate dansylamide binding, which rationalizes the enhanced dansylamide affinity measured for certain Leu-198 variants (Nair, S. K., Krebs, J.F., Christianson, D. W., and Fierke, C. A. (1995) Biochemistry 34, 3981-3989). Modeling studies indicate that a second binding mode, in which the fused aromatic ring is rotated out of the hydrophobic pocket, is sterically feasible. Both experimentally observed and modeled binding modes have implications for new leads in the design of avid CAII inhibitors. Finally, the structure of the CAII-dansylamide complex has implications for its exploitation in zinc biosensor applications, and possible routes toward the optimization of fluorophore design are considered on the basis on this structure. Unexpected binding mode of the sulfonamide fluorophore 5-dimethylamino-1-naphthalene sulfonamide to human carbonic anhydrase II. Implications for the development of a zinc biosensor.,Nair SK, Elbaum D, Christianson DW J Biol Chem. 1996 Jan 12;271(2):1003-7. PMID:8557623[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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