Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-22T18:56:33.708Z Has data issue: false hasContentIssue false

An Adaptive, Finite Difference Solver for the Nonlinear Poisson-Boltzmann Equation with Applications to Biomolecular Computations

Published online by Cambridge University Press:  03 June 2015

Mohammad Mirzadeh*
Affiliation:
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA
Maxime Theillard*
Affiliation:
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA
Asdís Helgadöttir*
Affiliation:
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA
David Boy*
Affiliation:
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA
Frédéric Gibou*
Affiliation:
Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA Department of Computer Science, University of California, Santa Barbara, CA 93106, USA
Get access

Abstract

We present a solver for the Poisson-Boltzmann equation and demonstrate its applicability for biomolecular electrostatics computation. The solver uses a level set framework to represent sharp, complex interfaces in a simple and robust manner. It also uses non-graded, adaptive octree grids which, in comparison to uniform grids, drastically decrease memory usage and runtime without sacrificing accuracy. The basic solver was introduced in earlier works [16,27], and here is extended to address biomolecular systems. First, a novel approach of calculating the solvent excluded and the solvent accessible surfaces is explained; this allows to accurately represent the location of the molecule’s surface. Next, a hybrid finite difference/finite volume approach is presented for discretizing the nonlinear Poisson-Boltzmann equation and enforcing the jump boundary conditions at the interface. Since the interface is implicitly represented by a level set function, imposing the jump boundary conditions is straightforward and efficient.

Type
Research Article
Copyright
Copyright © Global Science Press Limited 2013

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1]Aftosmis, M. J., Berger, M. J., and Melton, J. E.Adaptive Cartesian Mesh Generation. In CRC Handbook of Mesh Generation (Contributed Chapter), 1998.Google Scholar
[2]Baker, N. A., Bashford, D., and Case, D. A.Implicit solvent electrostatics in biomolecular simulation. New Algorithms for Macromolecular Simulation, 49(5): 263295, 2006.Google Scholar
[3]Baker, N. A.Improving implicit solvent simulations: A Poisson-centric view. Curr. Opin. Struc. Biol., 15(2): 137143, April 2005.CrossRefGoogle ScholarPubMed
[4]Baker, N. A., Sept, D., Joseph, S., Holst, M. J., and McCammon, J. A.Electrostatics of nanosystems: Application to microtubules and the ribosome. Proc. Natl. Acad. Sci. USA, 98(18): 1003710041, August 2001.CrossRefGoogle ScholarPubMed
[5]Boschitsch, A. H. and Fenley, M. O.A fast and robust Poisson-Boltzmann solver based on adaptive cartesian grids. J. Chem. Theory Comput., 7(5): 15241540, 2011.Google Scholar
[6]Can, T., Chen, C.-I., and Wang, Y.-F.Efficient molecular surface generation using level-set methods. J. Mol. Graphics Modell., 25(4): 442454, 2006.Google Scholar
[7]Chen, J., Brooks, C. L., and Khandogin, J.Recent advances in implicit solvent-based methods for biomolecular simulations. Curr. Opin. Struc. Biol., 18(2): 140148, April 2008.Google Scholar
[8]Chen, L., Holst, M. J., and Xu, J.The finite element approximation of the nonlinear Poisson-Boltzmann equation. SIAM J. Nume. Anal., 45(6): 22982320, 2007.CrossRefGoogle Scholar
[9]Chern, I.-L., Liu, J.-G., and Wang, W. C.Accurate evaluation of electrostatics for macromolecules in solution. Methods Appl. Anal., 10: 309328, 2003.CrossRefGoogle Scholar
[10]Connolly, M. L.Analytical molecular surface calculation. J. Appl. Crystallogr., 16: 548558, 1983.Google Scholar
[11]Connolly, M. L.The molecular surface package. J. Mol. Graphics, 11(2): 139141, 1993.Google Scholar
[12]Fogolari, F., Brigo, A., and Molinari, H.The Poisson-Boltzmann equation for biomolecular electrostatics: A tool for structural biology. J. Mol. Recognit., 15 (6): 377392, 2002.CrossRefGoogle ScholarPubMed
[13]Geng, W., Yu, S., and Wei, G. W.Treatment of charge singularities in implicit solvent models. J. Chem. Phys, 127(11): 114106, 2007.Google Scholar
[14]Gilson, M. K., Sharp, K. A., and Honig, B. H.Calculating the electrostatic potential of molecules in solution: Method and error assessment. J. Comput. Chem., 9(4): 327335, June 1988.CrossRefGoogle Scholar
[15]Greer, J. and Bush, B. L.Macromolecular shape and surface maps by solvent exclusion. Proc. Natl. Acad. Sci. USA, 75(1): 303, 1978.Google Scholar
[16]Helgadottir, A. and Gibou, F.A Poisson-Boltzmann solver on irregular domains with Neumann or Robin boundary conditions on non-graded adaptive grid. J. Comput. Phys., 230: 38303848, 2011.Google Scholar
[17]Kirkwood, J.G.Theory of solutions of molecules containing widely separated charges with special application to zwitterions. J. Chem. Phys., 2(7): 351, 1934.Google Scholar
[18]Koehl, P.Electrostatics calculations: Latest methodological advances. Curr. Opin. Struc. Biol., 16(2): 142151, 2006.Google Scholar
[19]Lee, B. and Richards, F. M.The interpretation of protein structures: Estimation of static accessibility. J. Mol. Biol., 55(3): 379400, 1971.Google Scholar
[20]Dzubiella, J.McCammon, J. A.Cheng, L.-T. and Li, Bo.Application of the level-set method to the implicit solvation of nonpolar molecules. J. Chem. Phys., 127: 084503, 2007.Google Scholar
[21]Lu, B. Z., Zhou, Y. C., Holst, M. J., and McCammon, J. A.Recent Progress in numerical methods for the Poisson Boltzmann equation in biophysical applications. Commun. Comput. Phys., 3(5): 9731009, 2008.Google Scholar
[22]Micu, A. M., Bagheri, B., Ilin, A. V., Scott, L. R., and Pettitt, B. M.Numerical Considerations in the Computation of the electrostatic free energy of interaction within the Poisson-Boltzmann theory. J. Comput. Phys., 136: 263271, 1997.Google Scholar
[23]Min, C.Local level set method in high dimension and codimension. J. Comput. Phys., 200: 368382, 2004.Google Scholar
[24]Min, C. and Gibou, F.Geometric integration over irregular domains with application to level set methods. J. Comput. Phys., 226: 14321443, 2007.Google Scholar
[25]Min, C. and Gibou, F.A second order accurate level set method on non-graded adaptive Cartesian grids. J. Comput. Phys., 225: 300321, 2007.Google Scholar
[26]Min, C., Gibou, F., and Ceniceros, H.A supra-convergent finite difference scheme for the variable coefficient Poisson equation on non-graded grids. J. Comput. Phys., 218: 123140, 2006.Google Scholar
[27]Mirzadeh, M., Theillard, M., and Gibou, F.A second-order discretization of the nonlinear Poisson-Boltzmann equation over irregular geometries using non-graded adaptive Cartesian grids. J. Comput. Phys., 230: 21252140, 2010.Google Scholar
[28]Ng, Y-T., Min, C., and Gibou, F.An efficient fluid-solid coupling algorithm for single-phase flows. J. Comput. Phys., 228: 88078829, 2009.CrossRefGoogle Scholar
[29]Osher, S. and Fedkiw, R.Level Set Methods and Dynamic Implicit Surfaces. Springer-Verlag, 2002. New York, NY.Google Scholar
[30]Osher, S. and Sethian, J.Fronts propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulations. J. Comput. Phys., 79: 1249, 1988.Google Scholar
[31]Wei, G. W., Bates, P., and Zhao, S.Minimal molecular surfaces and their applications. J. Comput. Chem., 29: 380391, 2008.Google Scholar
[32]Pan, Q. and Tai, X-C.Model the solvent-excluded surface of 3d protein molecular structures using geometric pde-based level-set method. Commun. Comput. Phys., 6: 777792, 2009.Google Scholar
[33]Richards, F. M.Areas, Volumes, Packing, and Protein Structure. Annu. Rev. Biophys. Bio., 6(1): 151176, 1977.Google Scholar
[34]Samet, H.The Design and Analysis of Spatial Data Structures. Addison-Wesley, New York, 1989.Google Scholar
[35]Samet, H.Applications of Spatial Data Structures: Computer Graphics, Image Processing and GIS. Addison-Wesley, New York, 1990.Google Scholar
[36]Sanner, M. F. and Olson, A. J.Reduced surface: An efficient way to compute molecular surfaces. Biopolymers, 38(3): 305320, 1996.Google Scholar
[37]Sethian, J. A.Level Set Methods and Fast Marching Methods. Cambridge University Press, 1999. Cambridge.Google Scholar
[38]Sharp, K. A. and Honig, B.Calculating total electrostatic energies with the nonlinear Poisson-Boltzmann equation. J. Phys. Chem., 94(19): 76847692, September 1990.CrossRefGoogle Scholar
[39]Warwicker, J. and Watson, H. C.Calculation of the electric potential in the active site cleft due to alpha-helix dipoles. J. Mol. Biol., 157(4): 671679, 1982.Google Scholar
[40]Zhou, Y. C., Feig, M., and Wei, G. W.Highly accurate biomolecular electrostatics in continuum dielectric environments. J. Comput. Chem., 29: 8797, 2007.Google Scholar