Carbonic anhydrase (CA) IX is a plasma membrane-associated member of the -CA enzyme family, which is involved in solid tumor acidification. It is a marker of tumor hypoxia and a prognostic factor in several human cancers. An aberrant increase in CA IX expression in chronic hypoxia and during development of various carcinomas contributes to tumorigenesis through at least two mechanisms: pH regulation and cell adhesion control. Here we report the X-ray structure of the catalytic domain of CA IX in complex with a classical, clinically used sulfonamide inhibitor, acetazolamide. The structure reveals a typical -CA fold, which significantly differs from the other CA isozymes when the protein quaternary structure is considered. Thus, two catalytic domains of CA IX associate to form a dimer, which is stabilized by the formation of an intermolecular disulfide bond. The active site clefts and the PG domains are located on one face of the dimer, while the C-termini are located on the opposite face to facilitate protein anchoring to the cell membrane. A correlation between the threedimensional structure and the physiological role of the enzyme is here suggested, based on the measurement of the pH profile of the catalytic activity for the physiological reaction, CO2 hydration to bicarbonate and protons. On the basis of the structural differences observed between CA IX and the other membrane-associated -CAs, further prospects for the rational drug design of isozymespecific CA inhibitors are proposed, given that inhibition of this enzyme shows antitumor activity both in vitro and in vivo.

Crystal structure of the catalytic domain of the tumor-associated human carbonic anhydrase IX / V. Alterio;M. Hilvo;A. D. Fiore;C. T. Supuran;P. Pan;S. Parkkila;A. Scaloni;J. Pastorek;S. Pastorekova;C. Pedone;A. Scozzafava;S. M. Monti;G. D. Simone. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 1091-6490. - STAMPA. - 106:(2009), pp. 16233-16238. [10.1073/pnas.0908301106]

Crystal structure of the catalytic domain of the tumor-associated human carbonic anhydrase IX.

SUPURAN, CLAUDIU TRANDAFIR;SCOZZAFAVA, ANDREA;
2009

Abstract

Carbonic anhydrase (CA) IX is a plasma membrane-associated member of the -CA enzyme family, which is involved in solid tumor acidification. It is a marker of tumor hypoxia and a prognostic factor in several human cancers. An aberrant increase in CA IX expression in chronic hypoxia and during development of various carcinomas contributes to tumorigenesis through at least two mechanisms: pH regulation and cell adhesion control. Here we report the X-ray structure of the catalytic domain of CA IX in complex with a classical, clinically used sulfonamide inhibitor, acetazolamide. The structure reveals a typical -CA fold, which significantly differs from the other CA isozymes when the protein quaternary structure is considered. Thus, two catalytic domains of CA IX associate to form a dimer, which is stabilized by the formation of an intermolecular disulfide bond. The active site clefts and the PG domains are located on one face of the dimer, while the C-termini are located on the opposite face to facilitate protein anchoring to the cell membrane. A correlation between the threedimensional structure and the physiological role of the enzyme is here suggested, based on the measurement of the pH profile of the catalytic activity for the physiological reaction, CO2 hydration to bicarbonate and protons. On the basis of the structural differences observed between CA IX and the other membrane-associated -CAs, further prospects for the rational drug design of isozymespecific CA inhibitors are proposed, given that inhibition of this enzyme shows antitumor activity both in vitro and in vivo.
2009
106
16233
16238
V. Alterio;M. Hilvo;A. D. Fiore;C. T. Supuran;P. Pan;S. Parkkila;A. Scaloni;J. Pastorek;S. Pastorekova;C. Pedone;A. Scozzafava;S. M. Monti;G. D. Simone
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/367006
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