The coumarin-binding site in carbonic anhydrase: the antiepileptic lacosamide as an example
[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. 
Publication Abstract from PubMed
Coumarins constitute a general and totally new class of inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 184.108.40.206), binding at the entrance of the active site cavity. We report here that the coumarin-binding site in CAs may interact with diverse compounds, such as the antiepileptic drug lacosamide, which inhibits mammalian CAs I-XV, with inhibition constants in range of 331 nM to 4.56 microM. Its X-ray crystal structure in adduct with CA II reveals the molecular basis for this inhibition. Lacosamide was found in the coumarin-binding site, making favorable van der Waals interactions with Thr200, Asn67, Gln92, and Phe131. No interactions with the Zn(II) ion were evidenced in the CA II-lacosamide adduct. The coumarin-binding site may thus accommodate structurally diverse compounds which possess an inhibition mechanism distinct of that of sulfonamides. This finding opens new possibilities for designing CA inhibitors/activators with various biomedical applications.
The coumarin-binding site in carbonic anhydrase accommodates structurally diverse inhibitors: the antiepileptic lacosamide as an example and lead molecule for novel classes of carbonic anhydrase inhibitors.,Temperini C, Innocenti A, Scozzafava A, Parkkila S, Supuran CT J Med Chem. 2010 Jan 28;53(2):850-4. PMID:20028100
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.