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Title: Joint neutron crystallographic and NMR solution studies of Tyr residue ionization and hydrogen bonding: Implications for enzyme-mediated proton transfer

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America
 [1];  [1];  [1];  [2];  [3];  [4];  [5];  [6]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Julich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Garching (Germany)
  3. Technische Univ. Munchen, Garching (Germany)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Univ. of Florida, Gainesville, FL (United States)
  6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Julich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Garching (Germany)

Human carbonic anhydrase II (HCA II) uses a Zn-bound OH-/H2O mechanism to catalyze the reversible hydration of CO2. This catalysis also involves a separate proton transfer step, mediated by an ordered solvent network coordinated by hydrophilic residues. One of these residues, Tyr7, was previously shown to be deprotonated in the neutron crystal structure at pH 10. This observation indicated that Tyr7 has a perturbed pKa compared with free tyrosine. To further probe the pKa) of this residue, NMR spectroscopic measurements of [13C] Tyr-labeled holo HCA II (with active-site Zn present) were preformed to titrate all Tyr residues between pH 5.4-11.0. In addition, neutron studies of apo HCA II (with Zn removed from the active site) at pH 7.5 and holo HCA II at pH 6 were conducted. This detailed interrogation of tyrosines in HCA II by NMR and neutron crystallography revealed a significantly lowered pKa of Tyr7 and how pH and Tyr proximity to Zn affect hydrogen-bonding interactions.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
Grant/Contract Number:
AC52-06NA25396; AC05-00OR22725; 20110535ER
OSTI ID:
1236701
Alternate ID(s):
OSTI ID: 1261433
Report Number(s):
LA-UR-15-20968
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, Issue 18; ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 28 works
Citation information provided by
Web of Science

References (31)

Physiological Functions of the Alpha Class of Carbonic Anhydrases book September 2013
The catalytic mechanism of carbonic anhydrase: implications of a rate-limiting protolysis of water journal January 1988
Neutron Structure of Human Carbonic Anhydrase II: A Hydrogen-Bonded Water Network “Switch” Is Observed between pH 7.8 and 10.0 journal November 2011
Protonation and Reactivity towards Carbon Dioxide of the Mononuclear Tetrahedral Zinc and Cobalt Hydroxide Complexes, [Tp Bu t ,Me ]ZnOH and [Tp Bu t ,Me ]CoOH:  Comparison of the Reactivity of the Metal Hydroxide Function in Synthetic Analogues of Carbonic Anhydrase journal May 2003
Atomic Crystal and Molecular Dynamics Simulation Structures of Human Carbonic Anhydrase II:  Insights into the Proton Transfer Mechanism , journal March 2007
A Short, Strong Hydrogen Bond in the Active Site of Human Carbonic Anhydrase II journal January 2010
Solvent-Mediated Proton Transfer in Catalysis by Carbonic Anhydrase journal August 2007
Role of histidine 64 in the catalytic mechanism of human carbonic anhydrase II studied with a site-specific mutant journal September 1989
Tautomerism of Histidine 64 Associated with Proton Transfer in Catalysis of Carbonic Anhydrase journal January 2007
Structural and Kinetic Characterization of Active-Site Histidine as a Proton Shuttle in Catalysis by Human Carbonic Anhydrase II , journal February 2005
Speeding Up Proton Transfer in a Fast Enzyme:  Kinetic and Crystallographic Studies on the Effect of Hydrophobic Amino Acid Substitutions in the Active Site of Human Carbonic Anhydrase II journal March 2007
Effect of Active-site Mutation at Asn67 on the Proton Transfer Mechanism of Human Carbonic Anhydrase II journal August 2009
Kinetic and crystallographic studies of the role of tyrosine 7 in the active site of human carbonic anhydrase II journal February 2011
Generalized X-ray and neutron crystallographic analysis: more accurate and complete structures for biological macromolecules journal May 2009
Seeing the chemistry in biology with neutron crystallography journal January 2013
pK values of the ionizable groups of proteins journal May 2006
A summary of the measured p K values of the ionizable groups in folded proteins journal January 2008
pH Dependence of the Photoactive Yellow Protein Photocycle Recovery Reaction Reveals a New Late Photocycle Intermediate with a Deprotonated Chromophore journal December 2008
Structure, dynamics, and ionization equilibria of the tyrosine residues in Bacillus circulans xylanase journal September 2011
pKa measurements from nuclear magnetic resonance of tyrosine-150 in class C beta-lactamase journal April 2003
Quantitative dissection of hydrogen bond-mediated proton transfer in the ketosteroid isomerase active site journal June 2013
Proton Transfer in Carbonic Anhydrase Is Controlled by Electrostatics Rather than the Orientation of the Acceptor journal February 2008
Structural properties of human carbonic anhydrase II at pH 9.5 journal December 1991
Preferred Orientations of His64 in Human Carbonic Anhydrase II journal March 2007
Entrapment of Carbon Dioxide in the Active Site of Carbonic Anhydrase II journal September 2008
Carbon-13 nuclear magnetic resonance study of tyrosine titrations journal January 1974
Comprehensive Determination of Protein Tyrosine pKa Values for Photoactive Yellow Protein Using Indirect 13C NMR Spectroscopy journal February 2012
Exogenous Sphingosine-1-Phosphate Boosts Acclimatization in Rats Exposed to Acute Hypobaric Hypoxia: Assessment of Haematological and Metabolic Effects journal June 2014
“Proton Holes” in Long-Range Proton Transfer Reactions in Solution and Enzymes:  A Theoretical Analysis journal December 2006
Proton Transfer Dependence on Hydrogen-Bonding of Solvent to the Water Wire: A Theoretical Study journal December 2012
Characterizing the Use of Perdeuteration in NMR Studies of Large Proteins:13C,15N and1H Assignments of Human Carbonic Anhydrase II journal December 1996

Cited By (7)

Conformational exchange of aromatic side chains by 1H CPMG relaxation dispersion journal September 2018
Thermodynamic, kinetic, and structural parameterization of human carbonic anhydrase interactions toward enhanced inhibitor design journal January 2018
Exploration of the residues modulating the catalytic features of human carbonic anhydrase XIII by a site-specific mutagenesis approach journal January 2019
Carbonic Anhydrases: Role in pH Control and Cancer journal February 2018
Neutron Crystallography for the Study of Hydrogen Bonds in Macromolecules journal April 2017
Thermodynamic, kinetic, and structural parameterization of human carbonic anhydrase interactions toward enhanced inhibitor design text January 2018
Insights into the binding mode of sulphamates and sulphamides to hCA II: crystallographic studies and binding free energy calculations journal January 2017