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Rayani K, Hantz ER, Haji-Ghassemi O, Li AY, Spuches AM, Van Petegem F, Solaro RJ, Lindert S, Tibbits GF. The effect of Mg 2+ on Ca 2+ binding to cardiac troponin C in hypertrophic cardiomyopathy associated TNNC1 variants. FEBS J 2022; 289:7446-7465. [PMID: 35838319 PMCID: PMC9836626 DOI: 10.1111/febs.16578] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/14/2022] [Accepted: 07/13/2022] [Indexed: 01/14/2023]
Abstract
Cardiac troponin C (cTnC) is the critical Ca2+ -sensing component of the troponin complex. Binding of Ca2+ to cTnC triggers a cascade of conformational changes within the myofilament that culminate in force production. Hypertrophic cardiomyopathy (HCM)-associated TNNC1 variants generally induce a greater degree and duration of Ca2+ binding, which may underly the hypertrophic phenotype. Regulation of contraction has long been thought to occur exclusively through Ca2+ binding to site II of cTnC. However, work by several groups including ours suggest that Mg2+ , which is several orders of magnitude more abundant in the cell than Ca2+ , may compete for binding to the same cTnC regulatory site. We previously used isothermal titration calorimetry (ITC) to demonstrate that physiological concentrations of Mg2+ may decrease site II Ca2+ -binding in both N-terminal and full-length cTnC. Here, we explore the binding of Ca2+ and Mg2+ to cTnC harbouring a series of TNNC1 variants thought to be causal in HCM. ITC and thermodynamic integration (TI) simulations show that A8V, L29Q and A31S elevate the affinity for both Ca2+ and Mg2+ . Further, L48Q, Q50R and C84Y that are adjacent to the EF hand binding motif of site II have a more significant effect on affinity and the thermodynamics of the binding interaction. To the best of our knowledge, this work is the first to explore the role of Mg2+ in modifying the Ca2+ affinity of cTnC mutations linked to HCM. Our results indicate a physiologically significant role for cellular Mg2+ both at baseline and when elevated on modifying the Ca2+ binding properties of cTnC and the subsequent conformational changes which precede cardiac contraction.
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Affiliation(s)
- Kaveh Rayani
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
| | - Eric R Hantz
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - Alison Y Li
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
| | - Anne M Spuches
- Department of Chemistry, 300 Science and Technology, East Carolina University, Greenville, NC, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - R John Solaro
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, USA
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
- BC Children's Hospital Research Institute, Vancouver, Canada
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Binding affinity models for Falcipain inhibition based on the Linear Interaction Energy method. J Mol Graph Model 2016; 70:236-245. [DOI: 10.1016/j.jmgm.2016.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 02/04/2023]
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Fyta M, Netz RR. Ionic force field optimization based on single-ion and ion-pair solvation properties: Going beyond standard mixing rules. J Chem Phys 2012; 136:124103. [DOI: 10.1063/1.3693330] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Appendix 1: Published Force Field Parameters. REVIEWS IN COMPUTATIONAL CHEMISTRY 2007. [DOI: 10.1002/9780470125830.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Abstract
The binding affinity and selectivity of a new ionophore, [1(8)]starand (1), toward alkali metal cations in methanol were examined through NMR titration experiments and free energy perturbation (FEP) and molecular dynamics simulations. The preference was determined to be K(+) > Rb(+) > Cs(+) > Na(+) >> Li(+) in both FEP simulations and NMR experiments. The FEP simulation results were able to predict the relative binding free energies with errors less than 0.13 kcal/mol, except for the case between Li(+) and Na(+). The cation selectivity was rationalized by analyzing the radial distribution functions of the M-O and M-C distances of free metal cations in methanol and those of metal-ionophore complexes in methanol.
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Cummins PL, Gready JE. Coupled semiempirical quantum mechanics and molecular mechanics (QM/MM) calculations on the aqueous solvation free energies of ionized molecules. J Comput Chem 1999. [DOI: 10.1002/(sici)1096-987x(19990730)20:10<1028::aid-jcc5>3.0.co;2-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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7
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Melo A, Ramos MJ. The nature of trypsin-pancreatic trypsin inhibitor binding: free energy calculation of Tyr39-->Phe39 mutation in trypsin. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 50:382-7. [PMID: 9401923 DOI: 10.1111/j.1399-3011.1997.tb01198.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The main goal of this work is the detailed study of the binding interactions in the trypsin-pancreatic trypsin inhibitor (PTI) complex and, here, we present how meaningful the Tyr39-Ile19 interaction is to the stability of that particular complex using free energy methods. This knowledge should be very important in the design of new inhibitors for trypsin and enzymes homologous to it. In particular, it could help to decide whether it is possible to produce selective inhibitors for these enzymes by appropriate mutations of residues in the contact region of PTI.
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Affiliation(s)
- A Melo
- CEQUP/Departamento de Química, Faculdade de Ciências, Universidade do Porto, Portugal
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Cummins PL, Gready JE. Coupled semiempirical molecular orbital and molecular mechanics model (QM/MM) for organic molecules in aqueous solution. J Comput Chem 1997. [DOI: 10.1002/(sici)1096-987x(199709)18:12<1496::aid-jcc7>3.0.co;2-e] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Ranganathan S, Gready JE. Hybrid Quantum and Molecular Mechanical (QM/MM) Studies on the Pyruvate to l-Lactate Interconversion in l-Lactate Dehydrogenase. J Phys Chem B 1997. [DOI: 10.1021/jp971051u] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Shoba Ranganathan
- Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra ACT 2601, Australia
| | - Jill E. Gready
- Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra ACT 2601, Australia
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