1
|
Shams Ghamsary M, Ghiasi M, Naghavi SS. Insight into the activation mechanism of carbonic anhydrase(II) through 2-(2-aminoethyl)-pyridine: a promising pathway for enhanced enzymatic activity. Phys Chem Chem Phys 2024; 26:10382-10391. [PMID: 38502117 DOI: 10.1039/d3cp05687b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Activation of human carbonic anhydrase II (hCA II) holds great promise for treating memory loss symptoms associated with Alzheimer's disease. Despite its importance, the activation mechanism of hCA II has been largely overlooked in favor of the well-studied inhibition mechanism. To address this unexplored realm, we use first-principles calculations to tease out the activation mechanism of hCA II using 2-(2-aminoethyl)-pyridine (2-2AEPy), a promising in vitro activator. We explored both stepwise and concerted mechanisms via both available nitrogen sites of 2-2AEPy: (i) aminoethyl group (Nα) and (ii) pyridine ring (Nβ). Our results show that a concerted mechanism via Nα holds the key to hCA II activation. The activation process of the concerted mechanism exhibits the characteristics of an exergonic reaction, wherein the transition state resembles the reactant with a notably low imaginary frequency of 452.4i cm-1 and barrier height of 5.2 kcal mol-1. Such meager transition barriers propel the activation of hCA II at in vivo temperatures. These findings initiate future research into hCA II activation mechanisms and the development of efficient activators, which may lead to promising therapeutic interventions for Alzheimer's disease.
Collapse
Affiliation(s)
- Masoumeh Shams Ghamsary
- Department of Physical and Computational Chemistry, Shahid Beheshti University, Tehran 1983969411, Iran.
| | - Mina Ghiasi
- Department of Physical Chemistry and Nano chemistry, Faculty of Chemistry, Alzahra University, 1993893973, Tehran, Iran.
| | - S Shahab Naghavi
- Department of Physical and Computational Chemistry, Shahid Beheshti University, Tehran 1983969411, Iran.
| |
Collapse
|
2
|
Hull JA, Lee C, Kim JK, Lim SW, Park J, Park S, Lee SJ, Park G, Eom I, Kim M, Hyun H, Combs JE, Andring JT, Lomelino C, Kim CU, McKenna R. XFEL structure of carbonic anhydrase II: a comparative study of XFEL, NMR, X-ray and neutron structures. Acta Crystallogr D Struct Biol 2024; 80:194-202. [PMID: 38411550 PMCID: PMC10910541 DOI: 10.1107/s2059798324000482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/12/2024] [Indexed: 02/28/2024] Open
Abstract
The combination of X-ray free-electron lasers (XFELs) with serial femtosecond crystallography represents cutting-edge technology in structural biology, allowing the study of enzyme reactions and dynamics in real time through the generation of `molecular movies'. This technology combines short and precise high-energy X-ray exposure to a stream of protein microcrystals. Here, the XFEL structure of carbonic anhydrase II, a ubiquitous enzyme responsible for the interconversion of CO2 and bicarbonate, is reported, and is compared with previously reported NMR and synchrotron X-ray and neutron single-crystal structures.
Collapse
Affiliation(s)
- Joshua A. Hull
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Cheol Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jin Kyun Kim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Seon Woo Lim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaehyun Park
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
- Department of Chemical Engineering, POSTECH, Pohang 37673, Republic of Korea
| | - Sehan Park
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Sang Jae Lee
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Gisu Park
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Intae Eom
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Minseok Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - HyoJung Hyun
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Jacob E. Combs
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jacob T. Andring
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Carrie Lomelino
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Chae Un Kim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| |
Collapse
|
3
|
Kariev AM, Green ME. Water, Protons, and the Gating of Voltage-Gated Potassium Channels. MEMBRANES 2024; 14:37. [PMID: 38392664 PMCID: PMC10890431 DOI: 10.3390/membranes14020037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/17/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
Ion channels are ubiquitous throughout all forms of life. Potassium channels are even found in viruses. Every cell must communicate with its surroundings, so all cells have them, and excitable cells, in particular, especially nerve cells, depend on the behavior of these channels. Every channel must be open at the appropriate time, and only then, so that each channel opens in response to the stimulus that tells that channel to open. One set of channels, including those in nerve cells, responds to voltage. There is a standard model for the gating of these channels that has a section of the protein moving in response to the voltage. However, there is evidence that protons are moving, rather than protein. Water is critical as part of the gating process, although it is hard to see how this works in the standard model. Here, we review the extensive evidence of the importance of the role of water and protons in gating these channels. Our principal example, but by no means the only example, will be the Kv1.2 channel. Evidence comes from the effects of D2O, from mutations in the voltage sensing domain, as well as in the linker between that domain and the gate, and at the gate itself. There is additional evidence from computations, especially quantum calculations. Structural evidence comes from X-ray studies. The hydration of ions is critical in the transfer of ions in constricted spaces, such as the gate region and the pore of a channel; we will see how the structure of the hydrated ion fits with the structure of the channel. In addition, there is macroscopic evidence from osmotic experiments and streaming current measurements. The combined evidence is discussed in the context of a model that emphasizes the role of protons and water in gating these channels.
Collapse
Affiliation(s)
- Alisher M Kariev
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA
| | - Michael E Green
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA
| |
Collapse
|
4
|
Rai D, Mondal D, Taraphder S. pH-Dependent Structure and Dynamics of the Catalytic Domains of Human Carbonic Anhydrase II and IX. J Phys Chem B 2023; 127:10279-10294. [PMID: 37983689 DOI: 10.1021/acs.jpcb.3c04721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Extensive computer simulation studies have been carried out to probe the pH-dependent structure and dynamics of the two most efficient isoenzymes II and IX of human carbonic anhydrase (HCA) that control the pH in the human body. The equilibrium structure and hydration of their catalytic domains are found to be largely unaffected by the variation of pH in the range studied, in close agreement with the known experimental results. In contrast, a significant effect of the change in pH is observed for the first time on the local electrostatic potential of the active site walls and the dynamics of active site water molecules. We also report for the first time the free energy and kinetics of coupled fluctuations of orientation and protonation states of the well-known His-mediated proton shuttle (His-64) in both isozymes at pH 7 and 8. The transitions between different tautomers of in or out conformations of His-64 side chain range between 109 and 106 s-1 depending on pH. Possible implications of these results on conformation-dependent pKa of His-64 side chain and its role in driving the catalysis toward hydration of CO2 or dehydration of HCO3- with varying pH are discussed.
Collapse
Affiliation(s)
- Divya Rai
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Dulal Mondal
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| |
Collapse
|
5
|
Rai D, Khatua S, Taraphder S. Structure and Dynamics of the Isozymes II and IX of Human Carbonic Anhydrase. ACS OMEGA 2022; 7:31149-31166. [PMID: 36092600 PMCID: PMC9453958 DOI: 10.1021/acsomega.2c03356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Human carbonic anhydrases (HCAs) are responsible for the pH control and sensing in our body and constitute key components in the central pH paradigm connected to cancer therapeutics. However, little or no molecular level studies are available on the pH-dependent stability and functional dynamics of the known isozymes of HCA. The main objective of this Article is to report the first bench-marking study on the structure and dynamics of the two most efficient isozymes, HCA II and IX, at neutral pH using classical molecular dynamics (MD) and constant pH MD (CpHMD) simulations combined with umbrella sampling, transition path sampling, and Markov state models. Starting from the known crystal structures of HCA II and the monomeric catalytic domain of HCA IX (labeled as HCA IX-c), we have generated classical MD and CpHMD trajectories (of length 1 μs each). In all cases, the overall stability, RMSD, and secondary structure segments of the two isozymes are found to be quite similar. Functionally important dynamics of these two enzymes have been probed in terms of active site hydration, coordination of the Zn(II) ion to a transient excess water, and the formation of putative proton transfer paths. The most important difference between the two isozymes is observed for the side-chain fluctuations of His-64 that is expected to shuttle an excess proton out of the active site as a part of the rate-determining intramolecular proton transfer reaction. The relative stability of the stable inward and outward conformations of the His-64 side-chain and the underlying free energy surfaces are found to depend strongly on the isozyme. In each case, a lower free energy barrier is detected between predominantly inward conformations from predominantly outward ones when simulated under constant pH conditions. The kinetic rate constants of interconversion between different free energy basins are found to span 107-108 s-1 with faster conformational transitions predicted at constant pH condition. The estimated rate constants and free energies are expected to validate if the fluctuation of the His-64 side-chain in HCA IX may have a significance similar to that known in the multistep catalytic cycle of HCA II.
Collapse
|
6
|
Kumar S, Deshpande PA. Efficient proton shuttle makes SazCA an excellent CO 2 hydration enzyme. J Biomol Struct Dyn 2022:1-10. [PMID: 35862658 DOI: 10.1080/07391102.2022.2100828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The fastest member of the carbonic anhydrase family catalysing the reversible hydration of carbon dioxide to bicarbonate ions has been recently reported to be SazCA. While thermostable, this enzyme shows exceptional activity at 353 K for the reaction. This study explores the molecular basis for the exceptional activity of SazCA, in contrast to SspCA, probed using molecular dynamics simulations. Our simulations, carried out at different temperatures, indicate the presence of efficient proton shuttle between the active zinc centre and His64 residue in the two enzymes. The proton accepting His64 residue was identified to have in and out conformations with the in conformations being supportive to proton acceptance. Our simulations show a large population of in conformations in SazCA making the enzyme exhibit an exceptional activity. The RMSF and H-bonds analysis confirmed the role of His2 and His207 in supporting the attainment of in conformations in SazCA resulting in exceptional activity.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Shashi Kumar
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Parag A Deshpande
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| |
Collapse
|
7
|
Nair AG, Perumalla DS, Anjukandi P. Towards solvent regulated self-activation of N-terminal disulfide bond oxidoreductase-D. Phys Chem Chem Phys 2022; 24:7691-7699. [PMID: 35311864 DOI: 10.1039/d1cp05819c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
N-terminal disulfide bond oxidoreductase-D (nDsbD), an essential redox enzyme in Gram-negative bacteria, consists of a single disulfide bond (Cys103-Cys109) in its active site. The enzymatic functions are believed to be regulated by an electron transfer mediated redox switching of the disulfide bond, which is vital in controlling bacterial virulence factors. In light of the disulfide bond's inclination towards nucleophilic cleavage, it is also plausible that an internal nucleophile could second the existing electron transfer mechanism in nDsbD. Using QM/MM MD metadynamics simulations, we explore different possibilities of generating an internal nucleophile near the nDsbD active site, which could serve as a fail-over mechanism in cleaving the disulfide bond. The simulations show the formation of the internal nucleophile Tyr42O- (F ≈ 9 kcal mol-1) and its stabilization through the solvent medium. The static gas-phase calculations show that Tyr42O- could be a potential nucleophile for cleaving the S-S bond. Most strikingly, it is also seen that Tyr42O- and Asp68OH communicate with each other through a proton-hole like water wire (F ≈ 12 kcal mol-1), thus modulating the nucleophile formation. Accordingly, we propose the role of a solvent in regulating the internal nucleophilic reactions and the subsequent self-activation of nDsbD. We believe that this could be deterministic while designing enzyme-targeted inhibitor compounds.
Collapse
Affiliation(s)
- Aparna G Nair
- Department of Chemistry, Indian Institute of Technology, Palakkad-678557, Kerala, India.
| | | | - Padmesh Anjukandi
- Department of Chemistry, Indian Institute of Technology, Palakkad-678557, Kerala, India.
| |
Collapse
|
8
|
Paul TK, Taraphder S. Nonlinear Reaction Coordinate of an Enzyme Catalyzed Proton Transfer Reaction. J Phys Chem B 2022; 126:1413-1425. [PMID: 35138854 DOI: 10.1021/acs.jpcb.1c08760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We present an in-depth study on the theoretical calculation of an optimum reaction coordinate as a linear or nonlinear combination of important collective variables (CVs) sampled from an ensemble of reactive transition paths for an intramolecular proton transfer reaction catalyzed by the enzyme human carbonic anhydrase (HCA) II. The linear models are optimized by likelihood maximization for a given number of CVs. The nonlinear models are based on an artificial neural network with the same number of CVs and optimized by minimizing the root-mean-square error in comparison to a training set of committor estimators generated for the given transition. The nonlinear reaction coordinate thus obtained yields the free energy of activation and rate constant as 9.46 kcal mol-1 and 1.25 × 106 s-1, respectively. These estimates are found to be in quantitative agreement with the known experimental results. We have also used an extended autoencoder model to show that a similar analysis can be carried out using a single CV only. The resultant free energies and kinetics of the reaction slightly overestimate the experimental data. The implications of these results are discussed using a detailed microkinetic scheme of the proton transfer reaction catalyzed by HCA II.
Collapse
Affiliation(s)
- Tanmoy Kumar Paul
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| |
Collapse
|
9
|
Sheff JG, Kelly JF, Robotham A, Sulea T, Malenfant F, L'Abbé D, Duchesne M, Pelletier A, Lefebvre J, Acel A, Parat M, Gosselin M, Wu C, Fortin Y, Baardsnes J, Van Faassen H, Awrey S, Chafe SC, McDonald PC, Dedhar S, Lenferink AEG. Hydrogen-deuterium exchange mass spectrometry reveals three unique binding responses of mAbs directed to the catalytic domain of hCAIX. MAbs 2021; 13:1997072. [PMID: 34812124 PMCID: PMC8632303 DOI: 10.1080/19420862.2021.1997072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human carbonic anhydrase (hCAIX), an extracellular enzyme that catalyzes the reversible hydration of CO2, is often overexpressed in solid tumors. This enzyme is instrumental in maintaining the survival of cancer cells in a hypoxic and acidic tumor microenvironment. Absent in most normal tissues, hCAIX is a promising therapeutic target for detection and treatment of solid tumors. Screening of a library of anti-hCAIX monoclonal antibodies (mAbs) previously identified three therapeutic candidates (mAb c2C7, m4A2 and m9B6) with distinct biophysical and functional characteristics. Selective binding to the catalytic domain was confirmed by yeast surface display and isothermal calorimetry, and deeper insight into the dynamic binding profiles of these mAbs upon binding were highlighted by bottom-up hydrogen-deuterium exchange mass spectrometry (HDX-MS). Here, a conformational and allosterically silent epitope was identified for the antibody-drug conjugate candidate c2C7. Unique binding profiles are described for both inhibitory antibodies, m4A2 and m9B6. M4A2 reduces the ability of the enzyme to hydrate CO2 by steric gating at the entrance of the catalytic cavity. Conversely, m9B6 disrupts the secondary structure that is necessary for substrate binding and hydration. The synergy of these two inhibitory mechanisms is demonstrated in in vitro activity assays and HDX-MS. Finally, the ability of m4A2 to modulate extracellular pH and intracellular metabolism is reported. By highlighting three unique modes by which hCAIX can be targeted, this study demonstrates both the utility of HDX-MS as an important tool in the characterization of anti-cancer biotherapeutics, and the underlying value of CAIX as a therapeutic target.
Collapse
Affiliation(s)
- Joey G Sheff
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - John F Kelly
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Anna Robotham
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Traian Sulea
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Félix Malenfant
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Denis L'Abbé
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Mélanie Duchesne
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Alex Pelletier
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Jean Lefebvre
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Andrea Acel
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Marie Parat
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Mylene Gosselin
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Cunle Wu
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Yves Fortin
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Jason Baardsnes
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| | - Henk Van Faassen
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Shannon Awrey
- Department of Integrative Oncology, Bc Cancer Research Institute, Vancouver, BC, Canada
| | - Shawn C Chafe
- Department of Integrative Oncology, Bc Cancer Research Institute, Vancouver, BC, Canada
| | - Paul C McDonald
- Department of Integrative Oncology, Bc Cancer Research Institute, Vancouver, BC, Canada
| | - Shoukat Dedhar
- Department of Integrative Oncology, Bc Cancer Research Institute, Vancouver, BC, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Anne E G Lenferink
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
| |
Collapse
|
10
|
Post-translational modifications in tumor-associated carbonic anhydrases. Amino Acids 2021; 54:543-558. [PMID: 34436666 DOI: 10.1007/s00726-021-03063-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/05/2021] [Indexed: 12/31/2022]
Abstract
Human carbonic anhydrases IX (hCA IX) and XII (hCA XII) are two proteins associated with tumor formation and development. These enzymes have been largely investigated both from a biochemical and a functional point of view. However, limited data are currently available on the characterization of their post-translational modifications (PTMs) and the functional implication of these structural changes in the tumor environment. In this review, we summarize existing literature data on PTMs of hCA IX and hCA XII, such as disulphide bond formation, phosphorylation, O-/N-linked glycosylation, acetylation and ubiquitination, highlighting, when possible, their specific role in cancer pathological processes.
Collapse
|
11
|
Fu Y, Fan F, Zhang Y, Wang B, Cao Z. Conformational Change of H64 and Substrate Transportation: Insight Into a Full Picture of Enzymatic Hydration of CO 2 by Carbonic Anhydrase. Front Chem 2021; 9:706959. [PMID: 34307302 PMCID: PMC8299336 DOI: 10.3389/fchem.2021.706959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
The enzymatic hydration of CO2 into HCO3 - by carbonic anhydrase (CA) is highly efficient and environment-friendly measure for CO2 sequestration. Here extensive MM MD and QM/MM MD simulations were used to explore the whole enzymatic process, and a full picture of the enzymatic hydration of CO2 by CA was achieved. Prior to CO2 hydration, the proton transfer from the water molecule (WT1) to H64 is the rate-limiting step with the free energy barrier of 10.4 kcal/mol, which leads to the ready state with the Zn-bound OH-. The nucleophilic attack of OH- on CO2 produces HCO3 - with the free energy barrier of 4.4 kcal/mol and the free energy release of about 8.0 kcal/mol. Q92 as the key residue manipulates both CO2 transportation to the active site and release of HCO3 -. The unprotonated H64 in CA prefers in an inward orientation, while the outward conformation is favorable energetically for its protonated counterpart. The conformational transition of H64 between inward and outward correlates with its protonation state, which is mediated by the proton transfer and the product release. The whole enzymatic cycle has the free energy span of 10.4 kcal/mol for the initial proton transfer step and the free energy change of -6.5 kcal/mol. The mechanistic details provide a comprehensive understanding of the entire reversible conversion of CO2 into bicarbonate and roles of key residues in chemical and nonchemical steps for the enzymatic hydration of CO2.
Collapse
Affiliation(s)
- Yuzhuang Fu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Fangfang Fan
- School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Yuwei Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Zexing Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| |
Collapse
|
12
|
Zanetti-Polzi L, Aschi M, Daidone I. Cooperative protein-solvent tuning of proton transfer energetics: carbonic anhydrase as a case study. Phys Chem Chem Phys 2021; 22:19975-19981. [PMID: 32857091 DOI: 10.1039/d0cp03652h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We investigate the coupling between the proton transfer (PT) energetics and the protein-solvent dynamics using the intra-molecular PT in wild type (wt) human carbonic anhydrase II and its ten-fold faster mutant Y7F/N67Q as a test case. We calculate the energy variation upon PT, and from that we also calculate the PT reaction free energy, making use of a hybrid quantum mechanics/molecular dynamics approach. In agreement with the experimental data, we obtain that the reaction free energy is basically the same in the two systems. Yet, we show that the instantaneous PT energy is on average lower in the mutant possibly contributing to the faster PT rate. Analysis of the contribution to the PT energetics of the solvent and of each protein residue, also not in the vicinity of the active site, provides evidence for electrostatic tuning of the PT energy arising from the combined effect of the solvent and the protein environment. These findings open up a way to the more general task of the rational design of mutants with either enhanced or reduced PT rate.
Collapse
Affiliation(s)
| | - Massimiliano Aschi
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, I-67010 L'Aquila, Italy.
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, I-67010 L'Aquila, Italy.
| |
Collapse
|
13
|
Wu Z, Nan Y, Zhao Y, Wang X, Huang S, Shi J. Immobilization of carbonic anhydrase for facilitated CO2 capture and separation. Chin J Chem Eng 2020. [DOI: 10.1016/j.cjche.2020.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
14
|
Jin S, Vullo D, Bua S, Nocentini A, Supuran CT, Gao YG. Structural and biochemical characterization of novel carbonic anhydrases from Phaeodactylum tricornutum. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2020; 76:676-686. [PMID: 32627740 DOI: 10.1107/s2059798320007202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/28/2020] [Indexed: 01/08/2023]
Abstract
Carbonic anhydrases (CAs) are a well characterized family of metalloenzymes that are highly efficient in facilitating the interconversion between carbon dioxide and bicarbonate. Recently, CA activity has been associated with the LCIB (limiting CO2-inducible protein B) protein family, which has been an interesting target in aquatic photosynthetic microorganisms. To gain further insight into the catalytic mechanism of this new group of CAs, the X-ray structure of a highly active LCIB homolog (PtLCIB3) from the diatom Phaeodactylum tricornutum was determined. The CA activities of PtLCIB3, its paralog PtLCIB4 and a variety of their mutants were also measured. It was discovered that PtLCIB3 has a classic β-CA fold and its overall structure is highly similar to that of its homolog PtLCIB4. Subtle structural alterations between PtLCIB3 and PtLCIB4 indicate that an alternative proton-shuttle cavity could perhaps be one reason for their remarkable difference in CA activity. A potential alternative proton-shuttle route in the LCIB protein family is suggested based on these results.
Collapse
Affiliation(s)
- Shengyang Jin
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Daniela Vullo
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Silvia Bua
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Alessio Nocentini
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Claudiu T Supuran
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Yong Gui Gao
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| |
Collapse
|
15
|
Paul TK, Taraphder S. Coordination Dynamics of Zinc Triggers the Rate Determining Proton Transfer in Human Carbonic Anhydrase II. Chemphyschem 2020; 21:1455-1473. [DOI: 10.1002/cphc.202000177] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/17/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Tanmoy Kumar Paul
- Department of Chemistry Indian Institute of Technology Kharagpur 721302 India
| | - Srabani Taraphder
- Department of Chemistry Indian Institute of Technology Kharagpur 721302 India
| |
Collapse
|
16
|
Palese LL. Oxygen-oxygen distances in protein-bound crystallographic water suggest the presence of protonated clusters. Biochim Biophys Acta Gen Subj 2020; 1864:129480. [DOI: 10.1016/j.bbagen.2019.129480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/27/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022]
|
17
|
Andring JT, Kim CU, McKenna R. Structure and mechanism of copper-carbonic anhydrase II: a nitrite reductase. IUCRJ 2020; 7:287-293. [PMID: 32148856 PMCID: PMC7055381 DOI: 10.1107/s2052252520000986] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/24/2020] [Indexed: 05/06/2023]
Abstract
Nitric oxide (NO) promotes vasodilation through the activation of guanylate cyclase, resulting in the relaxation of the smooth muscle vasculature and a subsequent decrease in blood pressure. Therefore, its regulation is of interest for the treatment and prevention of heart disease. An example is pulmonary hypertension which is treated by targeting this NO/vasodilation pathway. In bacteria, plants and fungi, nitrite (NO2 -) is utilized as a source of NO through enzymes known as nitrite reductases. These enzymes reduce NO2 - to NO through a catalytic metal ion, often copper. Recently, several studies have shown nitrite reductase activity of mammalian carbonic anhydrase II (CAII), yet the molecular basis for this activity is unknown. Here we report the crystal structure of copper-bound human CAII (Cu-CAII) in complex with NO2 - at 1.2 Å resolution. The structure exhibits Type 1 (T-1) and 2 (T-2) copper centers, analogous to bacterial nitrite reductases, both required for catalysis. The copper-substituted CAII active site is penta-coordinated with a 'side-on' bound NO2 -, resembling a T-2 center. At the N terminus, several residues that are normally disordered form a porphyrin ring-like configuration surrounding a second copper, acting as a T-1 center. A structural comparison with both apo- (without metal) and zinc-bound CAII (Zn-CAII) provides a mechanistic picture of how, in the presence of copper, CAII, with minimal conformational changes, can function as a nitrite reductase.
Collapse
Affiliation(s)
- Jacob T. Andring
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610 USA
| | - Chae Un Kim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610 USA
| |
Collapse
|
18
|
Sanyanga TA, Nizami B, Bishop ÖT. Mechanism of Action of Non-Synonymous Single Nucleotide Variations Associated with α-Carbonic Anhydrase II Deficiency. Molecules 2019; 24:E3987. [PMID: 31690045 PMCID: PMC6864701 DOI: 10.3390/molecules24213987] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 10/18/2019] [Accepted: 10/24/2019] [Indexed: 12/12/2022] Open
Abstract
Human carbonic anhydrase II (CA-II) is a Zinc (Zn 2 + ) metalloenzyme responsible for maintenance of acid-base balance within the body through the reversible hydration of CO 2 to produce protons (H + ) and bicarbonate (BCT). Due to its importance, alterations to the amino acid sequence of the protein as a result of single nucleotide variations (nsSNVs) have detrimental effects on homeostasis. Six pathogenic CA-II nsSNVs, K18E, K18Q, H107Y, P236H, P236R and N252D were identified, and variant protein models calculated using homology modeling. The effect of each nsSNV was analyzed using motif analysis, molecular dynamics (MD) simulations, principal component (PCA) and dynamic residue network (DRN) analysis. Motif analysis identified 11 functionally important motifs in CA-II. RMSD data indicated subtle SNV effects, while PCA analysis revealed that the presence of BCT results in greater conformational sampling and free energy in proteins. DRN analysis showed variant allosteric effects, and the average betweenness centrality (BC) calculations identified Glu117 as the most important residue for communication in CA-II. The presence of BCT was associated with a reduction to Glu117 usage in all variants, suggesting implications for Zn 2 + dissociation from the CA-II active site. In addition, reductions to Glu117 usage are associated with increases in the usage of the primary and secondary Zn 2 + ligands; His94, His96, His119 and Asn243 highlighting potential compensatory mechanisms to maintain Zn 2 + within the active site. Compared to traditional MD simulation investigation, DRN analysis provided greater insights into SNV mechanism of action, indicating its importance for the study of missense mutation effects in proteins and, in broader terms, precision medicine related research.
Collapse
Affiliation(s)
- Taremekedzwa Allan Sanyanga
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
| | - Bilal Nizami
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
| |
Collapse
|
19
|
Park D, Lee MS. Kinetic Study of CO 2 Hydration by Small-Molecule Catalysts with A Second Coordination Sphere that Mimic the Effect of the Thr-199 Residue of Carbonic Anhydrase. Biomimetics (Basel) 2019; 4:E66. [PMID: 31581538 PMCID: PMC6963681 DOI: 10.3390/biomimetics4040066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/11/2019] [Accepted: 09/27/2019] [Indexed: 02/06/2023] Open
Abstract
Zinc complexes were synthesized as catalysts that mimic the ability of carbonic anhydrase (CA) for the CO2 hydration reaction (H2O + CO2 → H+ + HCO3-). For these complexes, a tris(2-pyridylmethyl)amine (TPA) ligand mimicking only the active site, and a 6-((bis(pyridin-2-ylmethyl)amino)methyl)pyridin-2-ol (TPA-OH) ligand mimicking the hydrogen-bonding network of the secondary coordination sphere of CA were used. Potentiometric pH titration was used to determine the deprotonation ability of the Zn complexes, and their pKa values were found to be 8.0 and 6.8, respectively. Stopped-flow spectrophotometry was used to confirm the CO2 hydration rate. The rate constants were measured to be 648.4 and 730.6 M-1s-1, respectively. The low pKa value was attributed to the hydrogen-bonding network of the secondary coordination sphere of the catalyst that mimics the behavior of CA, and this was found to increase the CO2 hydration rate of the catalyst.
Collapse
Affiliation(s)
- DongKook Park
- Green Materials & Processes Group, Korea Institute of Industrial Technology (KITECH), 55, Jongga-ro, Jung-gu, Ulsan 44413, Korea.
| | - Man Sig Lee
- Green Materials & Processes Group, Korea Institute of Industrial Technology (KITECH), 55, Jongga-ro, Jung-gu, Ulsan 44413, Korea.
| |
Collapse
|
20
|
Park D, Lee MS. Kinetic study of catalytic CO 2 hydration by metal-substituted biomimetic carbonic anhydrase model complexes. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190407. [PMID: 31598240 PMCID: PMC6731748 DOI: 10.1098/rsos.190407] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/01/2019] [Indexed: 05/20/2023]
Abstract
The rapid rise of the CO2 level in the atmosphere has spurred the development of CO2 capture methods such as the use of biomimetic complexes that mimic carbonic anhydrase. In this study, model complexes with tris(2-pyridylmethyl)amine (TPA) were synthesized using various transition metals (Zn2+, Cu2+ and Ni2+) to control the intrinsic proton-donating ability. The pKa of the water coordinated to the metal, which indicates its proton-donating ability, was determined by potentiometric pH titration and found to increase in the order [(TPA)Cu(OH2)]2+ < [(TPA)Ni(OH2)]2+ < [(TPA)Zn(OH2)]2+. The effect of pKa on the CO2 hydration rate was investigated by stopped-flow spectrophotometry. Because the water ligand in [(TPA)Zn(OH2)]2+ had the highest pKa, it would be more difficult to deprotonate it than those coordinated to Cu2+ and Ni2+. It was, therefore, expected that the complex would have the slowest rate for the reaction of the deprotonated water with CO2 to form bicarbonate. However, it was confirmed that [(TPA)Zn(OH2)]2+ had the fastest CO2 hydration rate because the substitution of bicarbonate with water (bicarbonate release) occurred easily.
Collapse
Affiliation(s)
| | - Man Sig Lee
- Author for correspondence: Man Sig Lee e-mail:
| |
Collapse
|
21
|
Paul S, Nair NN, Vashisth H. Phase space and collective variable based simulation methods for studies of rare events. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1634268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sanjib Paul
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, USA
| | - Nisanth N. Nair
- Department of Chemistry, Indian Institute of Technology, Kanpur, India
| | - Harish Vashisth
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, USA
| |
Collapse
|
22
|
Paul S, Paul TK, Taraphder S. Orthogonal order parameters to model the reaction coordinate of an enzyme catalyzed reaction. J Mol Graph Model 2019; 90:18-32. [PMID: 30959266 DOI: 10.1016/j.jmgm.2019.03.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 03/01/2019] [Accepted: 03/26/2019] [Indexed: 01/03/2023]
Abstract
The choice of suitable collective variables in formulating an optimal reaction coordinate is a challenging task for activated transitions between a pair of stable states especially when dealing with biochemical changes such as enzyme catalyzed reactions. A detailed benchmarking study is carried out on the choice of collective variables that can distinguish between the stable states unambiguously. We specifically address the issue if these variables may be directly used to model the optimal reaction coordinate, or if it would be better to use their orthogonalized counterparts. The proposed computational scheme is applied to the rate determining intramolecular proton transfer step in the enzyme human carbonic anhydrase II. The optimum reaction coordinate is determined with and without orthogonalization of the collective variables pertinent to a key conformational fluctuation and the actual proton transfer step at the active site of the enzyme. Suitability of the predicted reaction coordinates in different processes is examined in terms of the free energy profile projected along the reaction coordinate, the rate constant of transition and the underlying molecular mechanism of barrier crossing. Our results indicate that a better agreement with earlier simulation and experimental data is obtained when the orthogonalized collective variables are used to model the reaction coordinate.
Collapse
Affiliation(s)
- Sanjib Paul
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Tanmoy Kumar Paul
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India.
| |
Collapse
|
23
|
Lomelino CL, Andring JT, McKenna R. Crystallography and Its Impact on Carbonic Anhydrase Research. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2018; 2018:9419521. [PMID: 30302289 PMCID: PMC6158936 DOI: 10.1155/2018/9419521] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/16/2018] [Indexed: 12/20/2022]
Abstract
X-ray and neutron crystallography are powerful techniques utilized to study the structures of biomolecules. Visualization of enzymes in complex with substrate/product and the capture of intermediate states can be related to activity to facilitate understanding of the catalytic mechanism. Subsequent analysis of small molecule binding within the enzyme active site provides insight into mechanisms of inhibition, supporting the design of novel inhibitors using a structure-guided approach. The first X-ray crystal structures were determined for small, ubiquitous enzymes such as carbonic anhydrase (CA). CAs are a family of zinc metalloenzymes that catalyze the hydration of CO2, producing HCO3 - and a proton. The CA structure and ping-pong mechanism have been extensively studied and are well understood. Though the function of CA plays an important role in a variety of physiological functions, CA has also been associated with diseases such as glaucoma, edema, epilepsy, obesity, and cancer and is therefore recognized as a drug target. In this review, a brief history of crystallography and its impact on CA research is discussed.
Collapse
Affiliation(s)
- Carrie L. Lomelino
- University of Florida College of Medicine, Department of Biochemistry and Molecular Biology, Gainesville, FL 32610, USA
| | - Jacob T. Andring
- University of Florida College of Medicine, Department of Biochemistry and Molecular Biology, Gainesville, FL 32610, USA
| | - Robert McKenna
- University of Florida College of Medicine, Department of Biochemistry and Molecular Biology, Gainesville, FL 32610, USA
| |
Collapse
|
24
|
Roston D, Lu X, Fang D, Demapan D, Cui Q. Analysis of Phosphoryl-Transfer Enzymes with QM/MM Free Energy Simulations. Methods Enzymol 2018; 607:53-90. [PMID: 30149869 DOI: 10.1016/bs.mie.2018.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We discuss the application of quantum mechanics/molecular mechanics (QM/MM) free energy simulations to the analysis of phosphoryl transfers catalyzed by two enzymes: alkaline phosphatase and myosin. We focus on the nature of the transition state and the issue of mechanochemical coupling, respectively, in the two enzymes. The results illustrate unique insights that emerged from the QM/MM simulations, especially concerning the interpretation of experimental data regarding the nature of enzymatic transition states and coupling between global structural transition and catalysis in the active site. We also highlight a number of technical issues worthy of attention when applying QM/MM free energy simulations, and comment on a number of technical and mechanistic issues that require further studies.
Collapse
Affiliation(s)
- Daniel Roston
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Madison, WI, United States
| | - Xiya Lu
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Madison, WI, United States
| | - Dong Fang
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Madison, WI, United States
| | - Darren Demapan
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Madison, WI, United States
| | - Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Madison, WI, United States.
| |
Collapse
|
25
|
Buonanno M, Di Fiore A, Langella E, D'Ambrosio K, Supuran CT, Monti SM, De Simone G. The Crystal Structure of a hCA VII Variant Provides Insights into the Molecular Determinants Responsible for Its Catalytic Behavior. Int J Mol Sci 2018; 19:ijms19061571. [PMID: 29795045 PMCID: PMC6032174 DOI: 10.3390/ijms19061571] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 05/07/2018] [Accepted: 05/19/2018] [Indexed: 01/07/2023] Open
Abstract
Although important progress has been achieved in understanding the catalytic mechanism of Carbonic Anhydrases, a detailed picture of all factors influencing the catalytic efficiency of the various human isoforms is still missing. In this paper we report a detailed structural study and theoretical pKa calculations on a hCA VII variant. The obtained data were compared with those already known for another thoroughly investigated cytosolic isoform, hCA II. Our structural studies show that in hCA VII the network of ordered water molecules, which connects the zinc bound solvent molecule to the proton shuttle His64, is altered compared to hCA II, causing a reduction of the catalytic efficiency. Theoretical calculations suggest that changes in solvent network are related to the difference in pKa of the proton shuttle in the two enzymes. The residue that plays a major role in determining the diverse pKa values of the proton shuttle is the one in position four, namely His for hCA II and Gly for hCA VII. This residue is located on the protein surface, outside of the active site cavity. These findings are in agreement with our previous studies that highlighted the importance of histidines on the protein surface of hCA II (among which His4) as crucial residues for the high catalytic efficiency of this isoform.
Collapse
Affiliation(s)
- Martina Buonanno
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Anna Di Fiore
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Emma Langella
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Katia D'Ambrosio
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Claudiu T Supuran
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via U. Schiff 6, 50019 Florence, Italy.
| | - Simona Maria Monti
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Giuseppina De Simone
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy.
| |
Collapse
|
26
|
Supuran CT, Alterio V, Di Fiore A, D' Ambrosio K, Carta F, Monti SM, De Simone G. Inhibition of carbonic anhydrase IX targets primary tumors, metastases, and cancer stem cells: Three for the price of one. Med Res Rev 2018; 38:1799-1836. [PMID: 29635752 DOI: 10.1002/med.21497] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/22/2018] [Accepted: 03/02/2018] [Indexed: 12/12/2022]
Abstract
Human carbonic anhydrase (CA) IX is a tumor-associated protein, since it is scarcely present in normal tissues, but highly overexpressed in a large number of solid tumors, where it actively contributes to survival and metastatic spread of tumor cells. Due to these features, the characterization of its biochemical, structural, and functional features for drug design purposes has been extensively carried out, with consequent development of several highly selective small molecule inhibitors and monoclonal antibodies to be used for different purposes. Aim of this review is to provide a comprehensive state-of-the-art of studies performed on this enzyme, regarding structural, functional, and biomedical aspects, as well as the development of molecules with diagnostic and therapeutic applications for cancer treatment. A brief description of additional pharmacologic applications for CA IX inhibition in other diseases, such as arthritis and ischemia, is also provided.
Collapse
Affiliation(s)
- Claudiu T Supuran
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | | | - Anna Di Fiore
- Istituto di Biostrutture e Bioimmagini-CNR, Naples, Italy
| | | | - Fabrizio Carta
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | | | | |
Collapse
|
27
|
Paul S, Paul TK, Taraphder S. Reaction Coordinate, Free Energy, and Rate of Intramolecular Proton Transfer in Human Carbonic Anhydrase II. J Phys Chem B 2018; 122:2851-2866. [DOI: 10.1021/acs.jpcb.7b10713] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sanjib Paul
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Tanmoy Kumar Paul
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| |
Collapse
|
28
|
Verma R, Mitchell-Koch K. In Silico Studies of Small Molecule Interactions with Enzymes Reveal Aspects of Catalytic Function. Catalysts 2017; 7:212. [PMID: 30464857 PMCID: PMC6241538 DOI: 10.3390/catal7070212] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Small molecules, such as solvent, substrate, and cofactor molecules, are key players in enzyme catalysis. Computational methods are powerful tools for exploring the dynamics and thermodynamics of these small molecules as they participate in or contribute to enzymatic processes. In-depth knowledge of how small molecule interactions and dynamics influence protein conformational dynamics and function is critical for progress in the field of enzyme catalysis. Although numerous computational studies have focused on enzyme-substrate complexes to gain insight into catalytic mechanisms, transition states and reaction rates, the dynamics of solvents, substrates, and cofactors are generally less well studied. Also, solvent dynamics within the biomolecular solvation layer play an important part in enzyme catalysis, but a full understanding of its role is hampered by its complexity. Moreover, passive substrate transport has been identified in certain enzymes, and the underlying principles of molecular recognition are an area of active investigation. Enzymes are highly dynamic entities that undergo different conformational changes, which range from side chain rearrangement of a residue to larger-scale conformational dynamics involving domains. These events may happen nearby or far away from the catalytic site, and may occur on different time scales, yet many are related to biological and catalytic function. Computational studies, primarily molecular dynamics (MD) simulations, provide atomistic-level insight and site-specific information on small molecule interactions, and their role in conformational pre-reorganization and dynamics in enzyme catalysis. The review is focused on MD simulation studies of small molecule interactions and dynamics to characterize and comprehend protein dynamics and function in catalyzed reactions. Experimental and theoretical methods available to complement and expand insight from MD simulations are discussed briefly.
Collapse
Affiliation(s)
- Rajni Verma
- Department of Chemistry, McKinley Hall, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA
| | - Katie Mitchell-Koch
- Department of Chemistry, McKinley Hall, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA
| |
Collapse
|
29
|
Abstract
Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.
Collapse
Affiliation(s)
| | - Kenneth M. Merz
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute of Cyber-Enabled Research, Michigan State University, East Lansing, Michigan 48824, United States
| |
Collapse
|
30
|
Taraphder S, Maupin CM, Swanson JJ, Voth GA. Coupling Protein Dynamics with Proton Transport in Human Carbonic Anhydrase II. J Phys Chem B 2016; 120:8389-404. [PMID: 27063577 PMCID: PMC5003118 DOI: 10.1021/acs.jpcb.6b02166] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/06/2016] [Indexed: 11/28/2022]
Abstract
The role of protein dynamics in enzyme catalysis is one of the most highly debated topics in enzymology. The main controversy centers around what may be defined as functionally significant conformational fluctuations and how, if at all, these fluctuations couple to enzyme catalyzed events. To shed light on this debate, the conformational dynamics along the transition path surmounting the highest free energy barrier have been herein investigated for the rate limiting proton transport event in human carbonic anhydrase (HCA) II. Special attention has been placed on whether the motion of an excess proton is correlated with fluctuations in the surrounding protein and solvent matrix, which may be rare on the picosecond and subpicosecond time scales of molecular motions. It is found that several active site residues, which do not directly participate in the proton transport event, have a significant impact on the dynamics of the excess proton. These secondary participants are shown to strongly influence the active site environment, resulting in the creation of water clusters that are conducive to fast, moderately slow, or slow proton transport events. The identification and characterization of these secondary participants illuminates the role of protein dynamics in the catalytic efficiency of HCA II.
Collapse
Affiliation(s)
- Srabani Taraphder
- Department
of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - C. Mark Maupin
- Department
of Chemical and Biological Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United
States
| | - Jessica
M. J. Swanson
- Department
of Chemistry, Institute for Biophysical Dynamics, James Frank Institute,
and Computation Institute, University of
Chicago, 5735 South Ellis
Avenue, Chicago, Illinois 60637, United States
| | - Gregory A. Voth
- Department
of Chemistry, Institute for Biophysical Dynamics, James Frank Institute,
and Computation Institute, University of
Chicago, 5735 South Ellis
Avenue, Chicago, Illinois 60637, United States
| |
Collapse
|
31
|
Mahon BP, Bhatt A, Socorro L, Driscoll JM, Okoh C, Lomelino CL, Mboge MY, Kurian JJ, Tu C, Agbandje-McKenna M, Frost SC, McKenna R. The Structure of Carbonic Anhydrase IX Is Adapted for Low-pH Catalysis. Biochemistry 2016; 55:4642-53. [PMID: 27439028 DOI: 10.1021/acs.biochem.6b00243] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Human carbonic anhydrase IX (hCA IX) expression in many cancers is associated with hypoxic tumors and poor patient outcome. Inhibitors of hCA IX have been used as anticancer agents with some entering Phase I clinical trials. hCA IX is transmembrane protein whose catalytic domain faces the extracellular tumor milieu, which is typically associated with an acidic microenvironment. Here, we show that the catalytic domain of hCA IX (hCA IX-c) exhibits the necessary biochemical and biophysical properties that allow for low pH stability and activity. Furthermore, the unfolding process of hCA IX-c appears to be reversible, and its catalytic efficiency is thought to be correlated directly with its stability between pH 3.0 and 8.0 but not above pH 8.0. To rationalize this, we determined the X-ray crystal structure of hCA IX-c to 1.6 Å resolution. Insights from this study suggest an understanding of hCA IX-c stability and activity in low-pH tumor microenvironments and may be applicable to determining pH-related effects on enzymes.
Collapse
Affiliation(s)
- Brian P Mahon
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Avni Bhatt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Lilien Socorro
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Jenna M Driscoll
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Cynthia Okoh
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Carrie L Lomelino
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Mam Y Mboge
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Justin J Kurian
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Chingkuang Tu
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Susan C Frost
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine , Gainesville, Florida 32610, United States
| |
Collapse
|
32
|
Kang K, Choi JM, Fox JM, Snyder PW, Moustakas DT, Whitesides GM. Acetylation of Surface Lysine Groups of a Protein Alters the Organization and Composition of Its Crystal Contacts. J Phys Chem B 2016; 120:6461-8. [DOI: 10.1021/acs.jpcb.6b01105] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kyungtae Kang
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
- Department
of Applied Chemistry, Kyung Hee University, 1732 Deogyeong-daero, Giheung, Yongin, Gyeonggi 17104, Republic of Korea
| | - Jeong-Mo Choi
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - Jerome M. Fox
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - Phillip W. Snyder
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - Demetri T. Moustakas
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - George M. Whitesides
- Department
of Chemistry and Chemical Biology, Harvard University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
- Wyss
Institute of Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, United States
| |
Collapse
|
33
|
Lee S, Liang R, Voth GA, Swanson JMJ. Computationally Efficient Multiscale Reactive Molecular Dynamics to Describe Amino Acid Deprotonation in Proteins. J Chem Theory Comput 2016; 12:879-91. [PMID: 26734942 PMCID: PMC4750100 DOI: 10.1021/acs.jctc.5b01109] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Indexed: 11/30/2022]
Abstract
An important challenge in the simulation of biomolecular systems is a quantitative description of the protonation and deprotonation process of amino acid residues. Despite the seeming simplicity of adding or removing a positively charged hydrogen nucleus, simulating the actual protonation/deprotonation process is inherently difficult. It requires both the explicit treatment of the excess proton, including its charge defect delocalization and Grotthuss shuttling through inhomogeneous moieties (water and amino residues), and extensive sampling of coupled condensed phase motions. In a recent paper (J. Chem. Theory Comput. 2014, 10, 2729-2737), a multiscale approach was developed to map high-level quantum mechanics/molecular mechanics (QM/MM) data into a multiscale reactive molecular dynamics (MS-RMD) model in order to describe amino acid deprotonation in bulk water. In this article, we extend the fitting approach (called FitRMD) to create MS-RMD models for ionizable amino acids within proteins. The resulting models are shown to faithfully reproduce the free energy profiles of the reference QM/MM Hamiltonian for PT inside an example protein, the ClC-ec1 H(+)/Cl(-) antiporter. Moreover, we show that the resulting MS-RMD models are computationally efficient enough to then characterize more complex 2-dimensional free energy surfaces due to slow degrees of freedom such as water hydration of internal protein cavities that can be inherently coupled to the excess proton charge translocation. The FitRMD method is thus shown to be an effective way to map ab initio level accuracy into a much more computationally efficient reactive MD method in order to explicitly simulate and quantitatively describe amino acid protonation/deprotonation in proteins.
Collapse
Affiliation(s)
| | | | - Gregory A. Voth
- Department of Chemistry,
Institute for Biophysical Dynamics, James Franck Institute, and Computation
Institute, University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Jessica M. J. Swanson
- Department of Chemistry,
Institute for Biophysical Dynamics, James Franck Institute, and Computation
Institute, University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| |
Collapse
|
34
|
Paul S, Taraphder S. Determination of the Reaction Coordinate for a Key Conformational Fluctuation in Human Carbonic Anhydrase II. J Phys Chem B 2015; 119:11403-15. [DOI: 10.1021/acs.jpcb.5b03655] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Sanjib Paul
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| |
Collapse
|
35
|
Shenderovich IG, Lesnichin SB, Tu C, Silverman DN, Tolstoy PM, Denisov GS, Limbach HH. NMR studies of active-site properties of human carbonic anhydrase II by using (15) N-labeled 4-methylimidazole as a local probe and histidine hydrogen-bond correlations. Chemistry 2014; 21:2915-29. [PMID: 25521423 DOI: 10.1002/chem.201404083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/12/2014] [Indexed: 12/24/2022]
Abstract
By using a combination of liquid and solid-state NMR spectroscopy, (15) N-labeled 4-methylimidazole (4-MI) as a local probe of the environment has been studied: 1) in the polar, wet Freon CDF3 /CDF2 Cl down to 130 K, 2) in water at pH 12, and 3) in solid samples of the mutant H64A of human carbonic anhydrase II (HCA II). In the latter, the active-site His64 residue is replaced by alanine; the catalytic activity is, however, rescued by the presence of 4-MI. For the Freon solution, it is demonstrated that addition of water molecules not only catalyzes proton tautomerism but also lifts its quasidegeneracy. The possible hydrogen-bond clusters formed and the mechanism of the tautomerism are discussed. Information about the imidazole hydrogen-bond geometries is obtained by establishing a correlation between published (1) H and (15) N chemical shifts of the imidazole rings of histidines in proteins. This correlation is useful to distinguish histidines embedded in the interior of proteins and those at the surface, embedded in water. Moreover, evidence is obtained that the hydrogen-bond geometries of His64 in the active site of HCA II and of 4-MI in H64A HCA II are similar. Finally, the degeneracy of the rapid tautomerism of the neutral imidazole ring His64 reported by Shimahara et al. (J. Biol. Chem.- 2007, 282, 9646) can be explained with a wet, polar, nonaqueous active-site conformation in the inward conformation, similar to the properties of 4-MI in the Freon solution. The biological implications for the enzyme mechanism are discussed.
Collapse
Affiliation(s)
- Ilya G Shenderovich
- University of Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany).
| | | | | | | | | | | | | |
Collapse
|
36
|
Falcón‐León MP, Tapia‐Benavides AR, Tlahuext H, Galán‐Vidal C, Suarez‐Castillo OR, Tlahuextl M. The Effect of Zn
II
Coordination on the Addition of 2‐(Aminomethyl)benzimidazole to Acrylonitrile. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Martha P. Falcón‐León
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca‐Tulancingo km 4.5, Hidalgo, México CP 42184, http://www.uaeh.edu.mx
| | - Antonio R. Tapia‐Benavides
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca‐Tulancingo km 4.5, Hidalgo, México CP 42184, http://www.uaeh.edu.mx
| | - Hugo Tlahuext
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Morelos, Mexico CP 62209
| | - Carlos Galán‐Vidal
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca‐Tulancingo km 4.5, Hidalgo, México CP 42184, http://www.uaeh.edu.mx
| | - Oscar R. Suarez‐Castillo
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca‐Tulancingo km 4.5, Hidalgo, México CP 42184, http://www.uaeh.edu.mx
| | - Margarita Tlahuextl
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca‐Tulancingo km 4.5, Hidalgo, México CP 42184, http://www.uaeh.edu.mx
| |
Collapse
|
37
|
Lacroix J, Soldera A, Lavoie J. A thermodynamic resolution of dimethyl carbonate decarboxylation and the first example of its reversibility: Dimethyl ether carboxylation. J CO2 UTIL 2014. [DOI: 10.1016/j.jcou.2014.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
38
|
Multiscale simulation reveals a multifaceted mechanism of proton permeation through the influenza A M2 proton channel. Proc Natl Acad Sci U S A 2014; 111:9396-401. [PMID: 24979779 DOI: 10.1073/pnas.1401997111] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The influenza A virus M2 channel (AM2) is crucial in the viral life cycle. Despite many previous experimental and computational studies, the mechanism of the activating process in which proton permeation acidifies the virion to release the viral RNA and core proteins is not well understood. Herein the AM2 proton permeation process has been systematically characterized using multiscale computer simulations, including quantum, classical, and reactive molecular dynamics methods. We report, to our knowledge, the first complete free-energy profiles for proton transport through the entire AM2 transmembrane domain at various pH values, including explicit treatment of excess proton charge delocalization and shuttling through the His37 tetrad. The free-energy profiles reveal that the excess proton must overcome a large free-energy barrier to diffuse to the His37 tetrad, where it is stabilized in a deep minimum reflecting the delocalization of the excess charge among the histidines and the cost of shuttling the proton past them. At lower pH values the His37 tetrad has a larger total charge that increases the channel width, hydration, and solvent dynamics, in agreement with recent 2D-IR spectroscopic studies. The proton transport barrier becomes smaller, despite the increased charge repulsion, due to backbone expansion and the more dynamic pore water molecules. The calculated conductances are in quantitative agreement with recent experimental measurements. In addition, the free-energy profiles and conductances for proton transport in several mutants provide insights for explaining our findings and those of previous experimental mutagenesis studies.
Collapse
|
39
|
Nelson JG, Peng Y, Silverstein DW, Swanson JMJ. Multiscale Reactive Molecular Dynamics for Absolute p Ka Predictions and Amino Acid Deprotonation. J Chem Theory Comput 2014; 10:2729-2737. [PMID: 25061442 PMCID: PMC4095931 DOI: 10.1021/ct500250f] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Indexed: 01/16/2023]
Abstract
Accurately calculating a weak acid's pKa from simulations remains a challenging task. We report a multiscale theoretical approach to calculate the free energy profile for acid ionization, resulting in accurate absolute pKa values in addition to insights into the underlying mechanism. Importantly, our approach minimizes empiricism by mapping electronic structure data (QM/MM forces) into a reactive molecular dynamics model capable of extensive sampling. Consequently, the bulk property of interest (the absolute pKa) is the natural consequence of the model, not a parameter used to fit it. This approach is applied to create reactive models of aspartic and glutamic acids. We show that these models predict the correct pKa values and provide ample statistics to probe the molecular mechanism of dissociation. This analysis shows changes in the solvation structure and Zundel-dominated transitions between the protonated acid, contact ion pair, and bulk solvated excess proton.
Collapse
Affiliation(s)
- J Gard Nelson
- Department of Chemistry, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago , 5735 S. Ellis Ave., Chicago, Illinois 60637, United States
| | - Yuxing Peng
- Department of Chemistry, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago , 5735 S. Ellis Ave., Chicago, Illinois 60637, United States
| | - Daniel W Silverstein
- Department of Chemistry, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago , 5735 S. Ellis Ave., Chicago, Illinois 60637, United States
| | - Jessica M J Swanson
- Department of Chemistry, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago , 5735 S. Ellis Ave., Chicago, Illinois 60637, United States
| |
Collapse
|
40
|
Aggarwal M, Kondeti B, Tu C, Maupin CM, Silverman DN, McKenna R. Structural insight into activity enhancement and inhibition of H64A carbonic anhydrase II by imidazoles. IUCRJ 2014; 1:129-35. [PMID: 25075329 PMCID: PMC4062085 DOI: 10.1107/s2052252514004096] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 02/21/2014] [Indexed: 05/31/2023]
Abstract
Human carbonic anhydrases (CAs) are zinc metalloenzymes that catalyze the hydration and dehydration of CO2 and HCO3 (-), respectively. The reaction follows a ping-pong mechanism, in which the rate-limiting step is the transfer of a proton from the zinc-bound solvent (OH(-)/H2O) in/out of the active site via His64, which is widely believed to be the proton-shuttling residue. The decreased catalytic activity (∼20-fold lower with respect to the wild type) of a variant of CA II in which His64 is replaced with Ala (H64A CA II) can be enhanced by exogenous proton donors/acceptors, usually derivatives of imidazoles and pyridines, to almost the wild-type level. X-ray crystal structures of H64A CA II in complex with four imidazole derivatives (imidazole, 1--methylimidazole, 2--methylimidazole and 4-methylimidazole) have been determined and reveal multiple binding sites. Two of these imidazole binding sites have been identified that mimic the positions of the 'in' and 'out' rotamers of His64 in wild-type CA II, while another directly inhibits catalysis by displacing the zinc-bound solvent. The data presented here not only corroborate the importance of the imidazole side chain of His64 in proton transfer during CA catalysis, but also provide a complete structural understanding of the mechanism by which imidazoles enhance (and inhibit when used at higher concentrations) the activity of H64A CA II.
Collapse
Affiliation(s)
- Mayank Aggarwal
- Department of Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, USA
| | - Bhargav Kondeti
- Department of Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, USA
| | - Chingkuang Tu
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100247, Gainesville, FL 32610, USA
| | - C. Mark Maupin
- Department of Chemical and Biological Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA
| | - David N. Silverman
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100247, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, USA
| |
Collapse
|
41
|
Boone CD, Pinard M, McKenna R, Silverman D. Catalytic mechanism of α-class carbonic anhydrases: CO2 hydration and proton transfer. Subcell Biochem 2014; 75:31-52. [PMID: 24146373 DOI: 10.1007/978-94-007-7359-2_3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The carbonic anhydrases (CAs; EC 4.2.1.1) are a family of metalloenzymes that catalyze the reversible hydration of carbon dioxide (CO2) and dehydration of bicarbonate (HCO3 (-)) in a two-step ping-pong mechanism: [Formula: see text] CAs are ubiquitous enzymes and are categorized into five distinct classes (α, β, γ, δ and ζ). The α-class is found primarily in vertebrates (and the only class of CA in mammals), β is observed in higher plants and some prokaryotes, γ is present only in archaebacteria whereas the δ and ζ classes have only been observed in diatoms.The focus of this chapter is on α-CAs as the structure-function relationship is best understood for this class, in particular for humans. The reader is referred to other reviews for an overview of the structure and catalytic mechanism of the other CA classes. The overall catalytic site structure and geometry of α-CAs are described in the first section of this chapter followed by the kinetic studies, binding of CO2, and the proton shuttle network.
Collapse
Affiliation(s)
- Christopher D Boone
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA,
| | | | | | | |
Collapse
|
42
|
Appraisal of sildenafil binding on the structure and promiscuous esterase activity of native and histidine-modified forms of carbonic anhydrase II. Biophys Chem 2013; 175-176:1-16. [DOI: 10.1016/j.bpc.2013.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 02/08/2013] [Accepted: 02/12/2013] [Indexed: 11/17/2022]
|
43
|
Koziol L, Essiz SG, Wong SE, Lau EY, Valdez CA, Satcher JH, Aines RD, Lightstone FC. Computational Analysis of a Zn-Bound Tris(imidazolyl) Calix[6]arene Aqua Complex: Toward Incorporating Second-Coordination Sphere Effects into Carbonic Anhydrase Biomimetics. J Chem Theory Comput 2013; 9:1320-7. [DOI: 10.1021/ct3008793] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lucas Koziol
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Sebnem G. Essiz
- Bioinformatics and Genetics
Department, Faculty of Engineering and Natural Sciences, Kadir Has University, 34083 Fatih, Istanbul, Turkey
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Sergio E. Wong
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Edmond Y. Lau
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Carlos A. Valdez
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Joe H. Satcher
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Roger D. Aines
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| | - Felice C. Lightstone
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California
94550, United States
| |
Collapse
|
44
|
Akdemir A, Vullo D, Luca VD, Scozzafava A, Carginale V, Rossi M, Supuran CT, Capasso C. The extremo-α-carbonic anhydrase (CA) from Sulfurihydrogenibium azorense, the fastest CA known, is highly activated by amino acids and amines. Bioorg Med Chem Lett 2013; 23:1087-90. [DOI: 10.1016/j.bmcl.2012.12.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 11/24/2022]
|
45
|
Mikulski R, West D, Sippel KH, Avvaru BS, Aggarwal M, Tu C, McKenna R, Silverman DN. Water networks in fast proton transfer during catalysis by human carbonic anhydrase II. Biochemistry 2012; 52:125-31. [PMID: 23215152 DOI: 10.1021/bi301099k] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Variants of human carbonic anhydrase II (HCA II) with amino acid replacements at residues in contact with water molecules in the active-site cavity have provided insights into the proton transfer rates in this protein environment. X-ray crystallography and (18)O exchange measured by membrane inlet mass spectrometry have been used to investigate structural and catalytic properties of variants of HCA II containing replacements of Tyr7 with Phe (Y7F) and Asn67 with Gln (N67Q). The rate constants for transfer of a proton from His64 to the zinc-bound hydroxide during catalysis were 4 and 9 μs(-1) for Y7F and Y7F/N67Q, respectively, compared with a value of 0.8 μs(-1) for wild-type HCA II. These higher values observed for Y7F and Y7F/N67Q HCA II could not be explained by differences in the values of the pK(a) of the proton donor (His64) and acceptor (zinc-bound hydroxide) or by the orientation of the side chain of the proton shuttle residue His64. They appeared to be associated with a reduced level of branching in the networks of hydrogen-bonded water molecules between proton shuttle residue His64 and the zinc-bound solvent molecule as observed in crystal structures at 1.5-1.6 Å resolution. Moreover, Y7F/N67Q HCA II is unique among the variants studied in having a direct, hydrogen-bonded chain of water molecules between the zinc-bound solvent and N(ε) of His64. This study provides the clearest example to date of the relevance of ordered water structure to rate constants for proton transfer in catalysis by carbonic anhydrase.
Collapse
Affiliation(s)
- Rose Mikulski
- Department of Pharmacology, University of Florida, Gainesville, FL 32610, USA
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Bernadat G, Supuran CT, Iorga BI. Carbonic anhydrase binding site parameterization in OPLS-AA force field. Bioorg Med Chem 2012. [PMID: 23182217 DOI: 10.1016/j.bmc.2012.10.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The parameterization of carbonic anhydrase binding site in OPLS-AA force field was performed using quantum chemistry calculations. Both OH2 and OH(-) forms of the binding site were considered, showing important differences in terms of atomic partial charges. Three different parameterization protocols were used, and the results obtained highlighted the importance of including an extended binding site in the charge calculation. The force field parameters were subsequently validated using standard molecular dynamics simulations. The results presented in this work should greatly facilitate the use of molecular dynamics simulations for studying the carbonic anhydrase, and more generally, the metallo-enzymes.
Collapse
Affiliation(s)
- Guillaume Bernadat
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Labex LERMIT, Centre de Recherche de Gif, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
| | | | | |
Collapse
|
47
|
Modeling the structure and proton transfer pathways of the mutant His-107-Tyr of human carbonic anhydrase II. J Mol Model 2012; 19:289-98. [PMID: 22878862 DOI: 10.1007/s00894-012-1549-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/23/2012] [Indexed: 10/28/2022]
Abstract
We present molecular modeling of the structure and possible proton transfer pathways from the surface of the protein to the zinc-bound water molecule in the active site of the mutant His-107-Tyr of human carbonic anhydrase II (HCAII). No high-resolution structure or crystal structure is available till now for this particular mutant due to its lack of stability at physiological temperature. Our analysis utilizes as starting point a series of structures derived from high-resolution crystal structure of the wild type protein. While many of the structures investigated do not reveal a complete path between the zinc bound water and His-64, several others do indicate the presence of a transient connection even when His-64 is present in its outward conformation. Mutation at the residue 107 also reveals the formation of a new path into the active site. Competing contributions from His-64 sidechain rotation from its outward conformation are also evaluated in terms of optimal path analysis. No indication of a lower catalytic efficiency of the mutant is evident from our results under the condition of thermal stability of the mutant.
Collapse
|
48
|
Koziol L, Valdez CA, Baker SE, Lau EY, Floyd WC, Wong SE, Satcher JH, Lightstone FC, Aines RD. Toward a Small Molecule, Biomimetic Carbonic Anhydrase Model: Theoretical and Experimental Investigations of a Panel of Zinc(II) Aza-Macrocyclic Catalysts. Inorg Chem 2012; 51:6803-12. [DOI: 10.1021/ic300526b] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lucas Koziol
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Carlos A. Valdez
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Sarah E. Baker
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Edmond Y. Lau
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - William C. Floyd
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Sergio E. Wong
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Joe H. Satcher
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Felice C. Lightstone
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| | - Roger D. Aines
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550, United States
| |
Collapse
|
49
|
Imtaiyaz Hassan M, Shajee B, Waheed A, Ahmad F, Sly WS. Structure, function and applications of carbonic anhydrase isozymes. Bioorg Med Chem 2012; 21:1570-82. [PMID: 22607884 DOI: 10.1016/j.bmc.2012.04.044] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/02/2012] [Accepted: 04/21/2012] [Indexed: 01/16/2023]
Abstract
The carbonic anhydrases enzymes (CAs, EC 4.2.1.1) are zinc containing metalloproteins, which efficiently catalyse the reversible conversion of carbon dioxide to bicarbonate and release proton. These enzymes are essentially important for biological system and play several important physiological and patho-physiological functions. There are 16 different alpha-carbonic anhydrase isoforms studied, differing widely in their cellular localization and biophysical properties. The catalytic domains of all CAs possess a conserved tertiary structure fold, with predominately β-strands. We performed an extensive analysis of all 16 mammalian CAs for its structure and function in order to establish a structure-function relationship. CAs have been a potential therapeutic target for many diseases. Sulfonamides are considered as a strong and specific inhibitor of CA, and are being used as diuretics, anti-glaucoma, anti-epileptic, anti-ulcer agents. Currently CA inhibitors are widely used as a drug for the treatment of neurological disorders, anti-glaucoma drugs, anti-cancer, or anti-obesity agents. Here we tried to emphasize how CAs can be used for drug discovery, design and screening. Furthermore, we discussed the role of CA in carbon capture, carbon sensor and metabolon. We hope this review provide many useful information on structure, function, mechanism, and applications of CAs in various discipline.
Collapse
Affiliation(s)
- Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
| | | | | | | | | |
Collapse
|
50
|
Peng Y, Voth GA. Expanding the view of proton pumping in cytochrome c oxidase through computer simulation. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:518-25. [PMID: 22178790 PMCID: PMC4120846 DOI: 10.1016/j.bbabio.2011.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 11/23/2011] [Accepted: 11/24/2011] [Indexed: 01/01/2023]
Abstract
In cytochrome c oxidase (CcO), a redox-driven proton pump, protons are transported by the Grotthuss shuttling via hydrogen-bonded water molecules and protonatable residues. Proton transport through the D-pathway is a complicated process that is highly sensitive to alterations in the amino acids or the solvation structure in the channel, both of which can inhibit proton pumping and enzymatic activity. Simulations of proton transport in the hydrophobic cavity showed a clear redox state dependence. To study the mechanism of proton pumping in CcO, multi-state empirical valence bond (MS-EVB) simulations have been conducted, focusing on the proton transport through the D-pathway and the hydrophobic cavity next to the binuclear center. The hydration structures, transport pathways, effects of residues, and free energy surfaces of proton transport were revealed in these MS-EVB simulations. The mechanistic insight gained from them is herein reviewed and placed in context for future studies.
Collapse
Affiliation(s)
- Yuxing Peng
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
| | - Gregory A. Voth
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, and Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
| |
Collapse
|