6s03 | pdb_00006s03
Carbonic Anhydrase CAIX mimic in complex with inhibitor I39LT379
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 PubMedThe DNA-linked inhibitor antibody assay (DIANA) has been recently validated for ultrasensitive enzyme detection and for quantitative evaluation of enzyme inhibitor potency. Here we present its adaptation for high-throughput screening of human carbonic anhydrase IX (CAIX), a promising drug and diagnostic target. We tested DIANA's performance by screening a unique compound collection of 2816 compounds consisting of lead-like small molecules synthesized at the Institute of Organic Chemistry and Biochemistry (IOCB) Prague ("IOCB library"). Additionally, to test the robustness of the assay and its potential for upscaling, we screened a pooled version of the IOCB library. The results from the pooled screening were in agreement with the initial nonpooled screen with no lost hits and no false positives, which shows DIANA's potential to screen more than 100,000 compounds per day. All DIANA screens showed a high signal-to-noise ratio with a Z' factor of >0.89. The DIANA screen identified 13 compounds with Ki values equal to or better than 10 microM. All retested hits were active also in an orthogonal enzymatic assay showing zero false positives. However, further biophysical validation of identified hits revealed that the inhibition activity of several hits was caused by a single highly potent CAIX inhibitor, being present as a minor impurity. This finding eventually led us to the identification of three novel CAIX inhibitors from the screen. We confirmed the validity of these compounds by elucidating their mode of binding into the CAIX active site by x-ray crystallography. Identification of Novel Carbonic Anhydrase IX Inhibitors Using High-Throughput Screening of Pooled Compound Libraries by DNA-Linked Inhibitor Antibody Assay (DIANA).,Tykvart J, Navratil V, Kugler M, Sacha P, Schimer J, Hlavackova A, Tenora L, Zemanova J, Dejmek M, Kral V, Potacek M, Majer P, Jahn U, Brynda J, Rezacova P, Konvalinka J SLAS Discov. 2020 May 26:2472555220918836. doi: 10.1177/2472555220918836. PMID:32452709[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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