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Title: A sucrose-binding site provides a lead towards an isoform-specific inhibitor of the cancer-associated enzyme carbonic anhydrase IX

Human carbonic anhydrase (CA; EC 4.2.1.1) isoform IX (CA IX) is an extracellular zinc metalloenzyme that catalyzes the reversible hydration of CO 2to HCO 3 $-$, thereby playing a role in pH regulation. The majority of normal functioning cells exhibit low-level expression of CA IX. However, in cancer cells CA IX is upregulated as a consequence of a metabolic transition known as the Warburg effect. The upregulation of CA IX for cancer progression has drawn interest in it being a potential therapeutic target. CA IX is a transmembrane protein, and its purification, yield and crystallization have proven challenging to structure-based drug design, whereas the closely related cytosolic soluble isoform CA II can be expressed and crystallized with ease. Therefore, we have utilized structural alignments and site-directed mutagenesis to engineer a CA II that mimics the active site of CA IX. In this paper, the X-ray crystal structure of this CA IX mimic in complex with sucrose is presented and has been refined to a resolution of 1.5 Å, anR cryst of 18.0% and anR free of 21.2%. Finally, the binding of sucrose at the entrance to the active site of the CA IX mimic, and not CA II, in amore » non-inhibitory mechanism provides a novel carbohydrate moiety binding site that could be further exploited to design isoform-specific inhibitors of CA IX.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1]
  1. Univ. of Florida, Gainesville, FL (United States). College of Medicine, Dept. of Biochemistry and Molecular Biology
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Division of Biology and Soft Matter
  3. Univ. of Florida, Gainesville, FL (United States). College of Medicine, Dept. of Pharmacology
Publication Date:
Grant/Contract Number:
AC05-00OR22725; GM25154
Type:
Accepted Manuscript
Journal Name:
Acta Crystallographica. Section F, Structural Biology Communications
Additional Journal Information:
Journal Volume: 71; Journal Issue: 10; Journal ID: ISSN 2053-230X
Publisher:
International Union of Crystallography
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; alpha-carbonic anhydrase; CA IX mimic; isoform-specific drug design; sugar approach; carbonic anhydrase IX; sucrose
OSTI Identifier:
1343505