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Dautel DR, Champion JA. Protein Vesicles Self-Assembled from Functional Globular Proteins with Different Charge and Size. Biomacromolecules 2020; 22:116-125. [PMID: 32886493 DOI: 10.1021/acs.biomac.0c00671] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein vesicles can be synthesized by mixing two fusion proteins: an elastin-like polypeptide (ELP) fused to an arginine-rich leucine zipper (ZR) with a globular, soluble protein fused to a glutamate-rich leucine zipper (ZE). Currently, only fluorescent proteins have been incorporated into vesicles; however, for protein vesicles to be useful for biocatalysis, drug delivery, or biosensing, vesicles must assemble from functional proteins that span an array of properties and functionalities. In this work, the globular protein was systematically changed to determine the effects of the surface charge and size on the self-assembly of protein vesicles. The formation of microphases, which included vesicles, coacervates, and hybrid structures, was monitored at different assembly conditions to determine the phase space for each globular protein. The results show that the protein surface charge has a small effect on vesicle self-assembly. However, increasing the size of the globular protein decreases the vesicle size and increases the stability at lower ZE/ZR molar ratios. The phase diagrams created can be used as guidelines to incorporate new functional proteins into vesicles. Furthermore, this work reports catalytically active enzyme vesicles, demonstrating the potential for the application of vesicles as biocatalysts or biosensors.
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Affiliation(s)
- Dylan R Dautel
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Julie A Champion
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States
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2
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Andring J, Combs J, McKenna R. Aspirin: A Suicide Inhibitor of Carbonic Anhydrase II. Biomolecules 2020; 10:biom10040527. [PMID: 32244293 PMCID: PMC7226357 DOI: 10.3390/biom10040527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 12/31/2022] Open
Abstract
Carbonic anhydrase II (CAII) is a metalloenzyme that catalyzes the reversible hydration/dehydration of CO2/HCO3−. In addition, CAII is attributed to other catalytic reactions, including esterase activity. Aspirin (acetyl-salicylic acid), an everyday over-the-counter drug, has both ester and carboxylic acid moieties. Recently, compounds with a carboxylic acid group have been shown to inhibit CAII. Hence, we hypothesized that Aspirin could act as a substrate for esterase activity, and the product salicylic acid (SA), an inhibitor of CAII. Here, we present the crystal structure of CAII in complex with SA, a product of CAII crystals pre-soaked with Aspirin, to 1.35Å resolution. In addition, we provide kinetic data to support the observation that CAII converts Aspirin to its deacetylated form, SA. This data may also explain the short half-life of Aspirin, with CAII so abundant in blood, and that Aspirin could act as a suicide inhibitor of CAII.
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Thermodynamic, kinetic, and structural parameterization of human carbonic anhydrase interactions toward enhanced inhibitor design. Q Rev Biophys 2019; 51:e10. [PMID: 30912486 DOI: 10.1017/s0033583518000082] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The aim of rational drug design is to develop small molecules using a quantitative approach to optimize affinity. This should enhance the development of chemical compounds that would specifically, selectively, reversibly, and with high affinity interact with a target protein. It is not yet possible to develop such compounds using computational (i.e., in silico) approach and instead the lead molecules are discovered in high-throughput screening searches of large compound libraries. The main reason why in silico methods are not capable to deliver is our poor understanding of the compound structure-thermodynamics and structure-kinetics correlations. There is a need for databases of intrinsic binding parameters (e.g., the change upon binding in standard Gibbs energy (ΔGint), enthalpy (ΔHint), entropy (ΔSint), volume (ΔVintr), heat capacity (ΔCp,int), association rate (ka,int), and dissociation rate (kd,int)) between a series of closely related proteins and a chemically diverse, but pharmacophoric group-guided library of compounds together with the co-crystal structures that could help explain the structure-energetics correlations and rationally design novel compounds. Assembly of these data will facilitate attempts to provide correlations and train data for modeling of compound binding. Here, we report large datasets of the intrinsic thermodynamic and kinetic data including over 400 primary sulfonamide compound binding to a family of 12 catalytically active human carbonic anhydrases (CA). Thermodynamic parameters have been determined by the fluorescent thermal shift assay, isothermal titration calorimetry, and by the stopped-flow assay of the inhibition of enzymatic activity. Kinetic measurements were performed using surface plasmon resonance. Intrinsic thermodynamic and kinetic parameters of binding were determined by dissecting the binding-linked protonation reactions of the protein and sulfonamide. The compound structure-thermodynamics and kinetics correlations reported here helped to discover compounds that exhibited picomolar affinities, hour-long residence times, and million-fold selectivities over non-target CA isoforms. Drug-lead compounds are suggested for anticancer target CA IX and CA XII, antiglaucoma CA IV, antiobesity CA VA and CA VB, and other isoforms. Together with 85 X-ray crystallographic structures of 60 compounds bound to six CA isoforms, the database should be of help to continue developing the principles of rational target-based drug design.
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4
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Ferraroni M, Gaspari R, Scozzafava A, Cavalli A, Supuran CT. Dioxygen, an unexpected carbonic anhydrase ligand. J Enzyme Inhib Med Chem 2018; 33:999-1005. [PMID: 29806484 PMCID: PMC6010096 DOI: 10.1080/14756366.2018.1475371] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Carbonic anhydrases (CAs, EC 4.2.1.1) are ubiquitous metalloenzymes, grouped into seven different classes, which catalyze the reaction of CO2 hydration to bicarbonate and protons. All of the fifteen human isoforms reported to date belong to the α-class and contain zinc as a cofactor. The structure of human Zn,Cu-CA II has been solved which contains a copper ion bound at its N-terminal, coordinated to His4 and His64. In the active site a dioxygen molecule is coordinated to the zinc ion. Since dioxygen is a rather unexpected CA ligand, molecular dynamics (MD) simulations were performed which suggested a superoxide character of the zinc bound O2.
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Affiliation(s)
- Marta Ferraroni
- a Dipartimento di Chimica , Università di Firenze , Sesto Fiorentino (FI) , Italia
| | | | - Andrea Scozzafava
- a Dipartimento di Chimica , Università di Firenze , Sesto Fiorentino (FI) , Italia
| | - Andrea Cavalli
- c Dipartimento di Farmacia e Biotecnologie , Università di Bologna , Bologna , Italia
| | - Claudiu T Supuran
- d Dipartimento NEUROFARBA - Pharmaceutical and Nutraceutical Section , Sesto Fiorentino (FI) , Italia
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5
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Mori M, Cau Y, Vignaroli G, Laurenzana I, Caivano A, Vullo D, Supuran CT, Botta M. Hit Recycling: Discovery of a Potent Carbonic Anhydrase Inhibitor by in Silico Target Fishing. ACS Chem Biol 2015; 10:1964-9. [PMID: 26121309 DOI: 10.1021/acschembio.5b00337] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In silico target fishing is an emerging tool in drug discovery, which is mostly used for primary target or off-target prediction and drug repositioning. In this work, we developed an in silico target fishing protocol to identify the primary target of GV2-20, a false-positive hit highlighted in a cell-based screen for 14-3-3 modulators. Although GV2-20 does not bind to 14-3-3 proteins, it showed remarkable antiproliferative effects in CML cells, thus raising interest toward the identification of its primary target. Six potential targets of GV2-20 were prioritized in silico and tested in vitro. Our results show that the molecule is a potent inhibitor of carbonic anhydrase 2 (CA2), thus confirming the predictive capability of our protocol. Most notably, GV2-20 experienced a remarkable selectivity for CA2, CA7, CA9, and CA12, and its scaffold was never explored before as a chemotype for CA inhibition, thus becoming an interesting lead candidate for further development.
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Affiliation(s)
- Mattia Mori
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, via Aldo Moro 2, I-53100 Siena, Italy
- Center
for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, viale Regina Elena 291, I-00161 Roma, Italy
| | - Ylenia Cau
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, via Aldo Moro 2, I-53100 Siena, Italy
| | - Giulia Vignaroli
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, via Aldo Moro 2, I-53100 Siena, Italy
| | - Ilaria Laurenzana
- IRCCS-Centro di Riferimento Oncologico Basilicata (CROB), Laboratory of Preclinical and Translational Research, Via Padre Pio 1, Rionero in Vulture 85028 Potenza, Italy
| | - Antonella Caivano
- IRCCS-Centro di Riferimento Oncologico Basilicata (CROB), Laboratory of Preclinical and Translational Research, Via Padre Pio 1, Rionero in Vulture 85028 Potenza, Italy
| | - Daniela Vullo
- Dipartimento
di Chimica, Laboratorio di Chimica Bioinorganica, Università degli Studi di Firenze, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy
| | - Claudiu T. Supuran
- Dipartimento
di Chimica, Laboratorio di Chimica Bioinorganica, Università degli Studi di Firenze, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy
- Dipartimento
NEUROFARBA, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Firenze), Italy
| | - Maurizio Botta
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, via Aldo Moro 2, I-53100 Siena, Italy
- Sbarro Institute
for Cancer Research and Molecular Medicine, Center for Biotechnology,
College of Science and Technology, Temple University, BioLife Science
Building, Suite 333, 1900 N 12th Street, Philadelphia, Pennsylvania 19122, United States
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West D, Pinard MA, Tu C, Silverman DN, McKenna R. Human carbonic anhydrase II-cyanate inhibitor complex: putting the debate to rest. Acta Crystallogr F Struct Biol Commun 2014; 70:1324-7. [PMID: 25286933 PMCID: PMC4188073 DOI: 10.1107/s2053230x14018135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/07/2014] [Indexed: 01/13/2024] Open
Abstract
The binding of anions to carbonic anhydrase II (CA II) has been attributed to high affinity for the active-site zinc. An anion of interest is cyanate, for which contrasting binding modes have been reported in the literature. Previous spectroscopic data have shown cyanate behaving as an inhibitor, directly binding to the zinc, in contrast to previous crystallographic data that implied that cyanate acts as a substrate mimic that is not directly bound to the zinc but overlaps with the binding site of the substrate CO2. Wild-type and the V207I variant of CA II have been expressed and X-ray crystal structures of their cyanate complexes have been determined to 1.7 and 1.5 Å resolution, respectively. The rationale for the V207I CA II variant was its close proximity to the CO2-binding site. Both structures clearly show that the cyanate binds directly to the zinc. In addition, inhibition constants (∼40 µM) were measured using (18)O-exchange mass spectrometry for wild-type and V207I CA II and were similar to those determined previously (Supuran et al., 1997). Hence, it is concluded that under the conditions of these experiments the binding of cyanate to CA II is directly to the zinc, displacing the zinc-bound solvent molecule, and not in a site that overlaps with the CO2 substrate-binding site.
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Affiliation(s)
- Dayne West
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - Melissa A. Pinard
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - Chingkuang Tu
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA
| | - David N. Silverman
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
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7
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Comparison and analysis of zinc and cobalt-based systems as catalytic entities for the hydration of carbon dioxide. PLoS One 2013; 8:e66187. [PMID: 23840420 PMCID: PMC3688778 DOI: 10.1371/journal.pone.0066187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/05/2013] [Indexed: 11/19/2022] Open
Abstract
In nature, the zinc metalloenzyme carbonic anhydrase II (CAII) efficiently catalyzes the conversion of carbon dioxide (CO2) to bicarbonate under physiological conditions. Many research efforts have been directed towards the development of small molecule mimetics that can facilitate this process and thus have a beneficial environmental impact, but these efforts have met very limited success. Herein, we undertook quantum mechanical calculations of four mimetics, 1,5,9-triazacyclododedacane, 1,4,7,10-tetraazacyclododedacane, tris(4,5-dimethyl-2-imidazolyl)phosphine, and tris(2-benzimidazolylmethyl)amine, in their complexed form either with the Zn2+ or the Co2+ ion and studied their reaction coordinate for CO2 hydration. These calculations demonstrated that the ability of the complex to maintain a tetrahedral geometry and bind bicarbonate in a unidentate manner were vital for the hydration reaction to proceed favorably. Furthermore, these calculations show that the catalytic activity of the examined zinc complexes was insensitive to coordination states for zinc, while coordination states above four were found to have an unfavorable effect on product release for the cobalt counterparts.
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8
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Di Fiore A, Monti SM, Hilvo M, Parkkila S, Romano V, Scaloni A, Pedone C, Scozzafava A, Supuran CT, De Simone G. Crystal structure of human carbonic anhydrase XIII and its complex with the inhibitor acetazolamide. Proteins 2009; 74:164-75. [DOI: 10.1002/prot.22144] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Krishnamurthy VM, Kaufman GK, Urbach AR, Gitlin I, Gudiksen KL, Weibel DB, Whitesides GM. Carbonic anhydrase as a model for biophysical and physical-organic studies of proteins and protein-ligand binding. Chem Rev 2008; 108:946-1051. [PMID: 18335973 PMCID: PMC2740730 DOI: 10.1021/cr050262p] [Citation(s) in RCA: 561] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Vijay M. Krishnamurthy
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - George K. Kaufman
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - Adam R. Urbach
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - Irina Gitlin
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - Katherine L. Gudiksen
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - Douglas B. Weibel
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138
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10
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Mazumdar PA, Kumaran D, Swaminathan S, Das AK. A novel acetate-bound complex of human carbonic anhydrase II. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:163-6. [PMID: 18323598 PMCID: PMC2374158 DOI: 10.1107/s1744309108002078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Accepted: 01/21/2008] [Indexed: 11/10/2022]
Abstract
The enzyme human carbonic anhydrase II (hCAII) crystallized in an acetate-bound complex belonging to space group P2(1)2(1)2(1), with unit-cell parameters a = 42.3, b = 71.8, c = 74.0 A. The structure was solved by the molecular-replacement method and refined to an R value of 0.18 and an R(free) of 0.21. The acetate molecule replaced the zinc-bound water molecule in the structure, differing from previous reports regarding the site of acetate binding. This mode of binding disrupts the hydrogen-bonded solvent network required for activity of the enzyme. This mode of inhibitor binding is a novel one that has not been observed previously.
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Affiliation(s)
- Pooja Anjali Mazumdar
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Desigan Kumaran
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | | | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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Premkumar L, Greenblatt HM, Bageshwar UK, Savchenko T, Gokhman I, Sussman JL, Zamir A. Three-dimensional structure of a halotolerant algal carbonic anhydrase predicts halotolerance of a mammalian homolog. Proc Natl Acad Sci U S A 2005; 102:7493-8. [PMID: 15894606 PMCID: PMC1111892 DOI: 10.1073/pnas.0502829102] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein molecular adaptation to drastically shifting salinities was studied in dCA II, an alpha-type carbonic anhydrase (EC 4.2.1.1) from the exceptionally salt-tolerant unicellular green alga Dunaliella salina. The salt-inducible, extracellular dCA II is highly salt-tolerant and thus differs from its mesophilic homologs. The crystal structure of dCA II, determined at 1.86-A resolution, is globally similar to other alpha-type carbonic anhydrases except for two extended alpha-helices and an added Na-binding loop. Its unusual electrostatic properties include a uniformly negative surface electrostatic potential of lower magnitude than that observed in the highly acidic halophilic proteins and an exceptionally low positive potential at a site adjoining the catalytic Zn(2+) compared with mesophilic homologs. The halotolerant dCA II also differs from typical halophilic proteins in retaining conformational stability and solubility in low to high salt concentrations. The crucial role of electrostatic features in dCA II halotolerance is strongly supported by the ability to predict the unanticipated halotolerance of the murine CA XIV isozyme, which was confirmed biochemically. A proposal for the functional significance of the halotolerance of CA XIV in the kidney is presented.
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Affiliation(s)
- Lakshmanane Premkumar
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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12
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Whittington DA, Grubb JH, Waheed A, Shah GN, Sly WS, Christianson DW. Expression, Assay, and Structure of the Extracellular Domain of Murine Carbonic Anhydrase XIV. J Biol Chem 2004; 279:7223-8. [PMID: 14660577 DOI: 10.1074/jbc.m310809200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbonic anhydrase (CA) XIV is the most recently identified mammalian carbonic anhydrase isozyme, and its presence has been demonstrated in a number of tissues. Full-length CA XIV is a transmembrane protein composed of an extracellular catalytic domain, a single transmembrane helix, and a short intracellular polypeptide segment. The amino acid sequence identity of human CA XIV relative to the other membrane-associated isozymes (CA IV, CA IX, and CA XII) is 34-46%. We report here the expression and purification of both the full-length enzyme and a truncated, secretory form of murine CA XIV. Both forms of this isozyme are highly active, and both show an abrogation of activity in the presence of 0.2% SDS, in contrast to the behavior of murine CA IV. We also report the crystal structure of the extracellular domain of murine CA XIV at 2.8 A resolution and of an enzyme-acetazolamide complex at 2.9 A resolution. The structure shows a monomeric glycoprotein with a topology similar to that of other mammalian CA isozymes. Based on the x-ray crystallographic results, we compare and contrast known structures of membrane-associated CA isozymes to rationalize the structural elements responsible for the SDS resistance of CA IV and to discuss prospects for the design of selective inhibitors of membrane-associated CA isozymes.
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Affiliation(s)
- Douglas A Whittington
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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13
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Whittington DA, Waheed A, Ulmasov B, Shah GN, Grubb JH, Sly WS, Christianson DW. Crystal structure of the dimeric extracellular domain of human carbonic anhydrase XII, a bitopic membrane protein overexpressed in certain cancer tumor cells. Proc Natl Acad Sci U S A 2001; 98:9545-50. [PMID: 11493685 PMCID: PMC55489 DOI: 10.1073/pnas.161301298] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2001] [Indexed: 01/06/2023] Open
Abstract
Overexpression of the zinc enzyme carbonic anhydrase (CA; EC ) XII is observed in certain human cancers. This bitopic membrane protein contains an N-terminal extracellular catalytic domain, a membrane-spanning alpha-helix, and a small intracellular C-terminal domain. We have determined the three-dimensional structure of the extracellular catalytic domain of human CA XII by x-ray crystallographic methods at 1.55-A resolution. The structure reveals a prototypical CA fold; however, two CA XII domains associate to form an isologous dimer, an observation that is confirmed by studies of the enzyme in solution. The identification of signature GXXXG and GXXXS motifs in the transmembrane sequence that facilitate helix-helix association is additionally consistent with dimeric architecture. The dimer interface is situated so that the active site clefts of each monomer are clearly exposed on one face of the dimer, and the C termini are located together on the opposite face of the dimer to facilitate membrane interaction. The amino acid composition of the active-site cleft closely resembles that of the other CA isozymes in the immediate vicinity of the catalytic zinc ion, but differs in the region of the nearby alpha-helical "130's segment." The structure of the CA XII-acetazolamide complex is also reported at 1.50-A resolution, and prospects for the design of CA XII-specific inhibitors of possible chemotherapeutic value are discussed.
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Affiliation(s)
- D A Whittington
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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