An effective Coarse‐grained model for biological simulations: Recent refinements and validations

Exploring the free energy landscape of proteins and modeling the corresponding functional aspects presents a major challenge for computer simulation approaches. This challenge is due to the complexity of the landscape and the enormous computer time needed for converging simulations. The use of various simplified coarse grained (CG) models offers an effective way of sampling the landscape, but most current models are not expected to give a reliable description of protein stability and functional aspects. The main problem is associated with insufficient focus on the electrostatic features of the model. In this respect, our recent CG model offers significant advantage as it has been refined while focusing on its electrostatic free energy. Here we review the current state of our model, describing recent refinements, extensions, and validation studies while focusing on demonstrating key applications. These include studies of protein stability, extending the model to include membranes, electrolytes and electrodes, as well as studies of voltage‐activated proteins, protein insertion through the translocon, the action of molecular motors, and even the coupling of the stalled ribosome and the translocon. The examples discussed here illustrate the general potential of our approach in overcoming major challenges in studies of structure function correlation in proteins and large macromolecular complexes. Proteins 2014; 82:1168–1185. © 2013 Wiley Periodicals, Inc.

[1]  Jakob P. Ulmschneider,et al.  Determining Peptide Partitioning Properties via Computer Simulation , 2010, The Journal of Membrane Biology.

[2]  Arieh Warshel,et al.  On the energetics of translocon-assisted insertion of charged transmembrane helices into membranes , 2010, Proceedings of the National Academy of Sciences.

[3]  Arieh Warshel,et al.  Coarse-grained (multiscale) simulations in studies of biophysical and chemical systems. , 2011, Annual review of physical chemistry.

[4]  Nir Ben-Tal,et al.  Interactions of the M2delta segment of the acetylcholine receptor with lipid bilayers: a continuum-solvent model study. , 2003, Biophysical journal.

[5]  Klaus Schulten,et al.  Free-energy cost for translocon-assisted insertion of membrane proteins , 2011, Proceedings of the National Academy of Sciences.

[6]  Arieh Warshel,et al.  Exploring the nature of the translocon-assisted protein insertion , 2012, Proceedings of the National Academy of Sciences.

[7]  K. Dill Dominant forces in protein folding. , 1990, Biochemistry.

[8]  Munehito Arai,et al.  Probing the interactions between the folding elements early in the folding of Escherichia coli dihydrofolate reductase by systematic sequence perturbation analysis. , 2005, Journal of molecular biology.

[9]  Thomas F. Miller,et al.  Long-timescale dynamics and regulation of Sec-facilitated protein translocation. , 2012, Cell reports.

[10]  Erik Lindahl,et al.  Protein contents in biological membranes can explain abnormal solvation of charged and polar residues , 2009, Proceedings of the National Academy of Sciences.

[11]  Joan-Emma Shea,et al.  Coarse-grained models for protein aggregation. , 2011, Current opinion in structural biology.

[12]  M. Levitt,et al.  A lattice model for protein structure prediction at low resolution. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[13]  F. Bezanilla How membrane proteins sense voltage , 2008, Nature Reviews Molecular Cell Biology.

[14]  Klaus Schulten,et al.  Biophysical Journal, Volume 98 Supporting Material Calculation of the Gating Charge for the Kv1.2 Voltage–activated Potassium Channel , 2022 .

[15]  A. Warshel,et al.  Energetics of ion permeation through membrane channels. Solvation of Na+ by gramicidin A. , 1989, Biophysical journal.

[16]  Martin Karplus,et al.  How subunit coupling produces the γ-subunit rotary motion in F1-ATPase , 2008, Proceedings of the National Academy of Sciences.

[17]  J. Onuchic,et al.  Folding funnels and frustration in off-lattice minimalist protein landscapes. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[18]  D. Rees,et al.  ABC transporters: the power to change , 2009, Nature Reviews Molecular Cell Biology.

[19]  Changbong Hyeon,et al.  Capturing the essence of folding and functions of biomolecules using coarse-grained models. , 2011, Nature communications.

[20]  George Oster,et al.  Energy transduction in the F1 motor of ATP synthase , 1998, Nature.

[21]  Arieh Warshel,et al.  Electrostatic origin of the mechanochemical rotary mechanism and the catalytic dwell of F1-ATPase , 2011, Proceedings of the National Academy of Sciences.

[22]  Arieh Warshel,et al.  Simulating the pulling of stalled elongated peptide from the ribosome by the translocon , 2013, Proceedings of the National Academy of Sciences.

[23]  T. E. Thompson,et al.  Semisynthetic proteins: model systems for the study of the insertion of hydrophobic peptides into preformed lipid bilayers. , 1994, Biochemistry.

[24]  Hendrik Sielaff,et al.  Torque generation and elastic power transmission in the rotary FOF1-ATPase , 2009, Nature.

[25]  K. Sharp,et al.  Electrostatic interactions in macromolecules: theory and applications. , 1990, Annual review of biophysics and biophysical chemistry.

[26]  Arieh Warshel,et al.  Coarse grained model for exploring voltage dependent ion channels. , 2012, Biochimica et biophysica acta.

[27]  A. Fersht,et al.  Transition-state structure as a unifying basis in protein-folding mechanisms: contact order, chain topology, stability, and the extended nucleus mechanism. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[28]  D. Tobias,et al.  Microscopic origin of gating current fluctuations in a potassium channel voltage sensor. , 2012, Biophysical journal.

[29]  R. G. Alden,et al.  Calculations of Electrostatic Energies in Photosynthetic Reaction Centers , 1995 .

[30]  Kyle A. Beauchamp,et al.  Molecular simulation of ab initio protein folding for a millisecond folder NTL9(1-39). , 2010, Journal of the American Chemical Society.

[31]  Björn Wallner,et al.  Tracking a complete voltage-sensor cycle with metal-ion bridges , 2012, Proceedings of the National Academy of Sciences.

[32]  M. Levitt,et al.  Computer simulation of protein folding , 1975, Nature.

[33]  N. Go,et al.  Studies on protein folding, unfolding and fluctuations by computer simulation. I. The effect of specific amino acid sequence represented by specific inter-unit interactions. , 2009 .

[34]  Roberto Livi,et al.  Coarse Grained Modeling and Approaches to Protein Folding , 2010 .

[35]  Lydia E Kavraki,et al.  From coarse‐grain to all‐atom: Toward multiscale analysis of protein landscapes , 2007, Proteins.

[36]  Arieh Warshel,et al.  Modeling electrostatic effects in proteins. , 2006, Biochimica et biophysica acta.

[37]  Gregory A. Voth Multiscale Simulation of Multiprotein Assemblies: The Challenges of Ultra-Coarse-Graining , 2013 .

[38]  N. Ben-Tal,et al.  Interactions of hydrophobic peptides with lipid bilayers: Monte Carlo simulations with M2delta. , 2003, Biophysical journal.

[39]  Toby W Allen,et al.  Potential of mean force and pKa profile calculation for a lipid membrane-exposed arginine side chain. , 2008, The journal of physical chemistry. B.

[40]  Volker Sieber,et al.  Surface‐exposed phenylalanines in the RNP1/RNP2 motif stabilize the cold‐shock protein CspB from Bacillus subtilis , 1998, Proteins.

[41]  A. Warshel Electrostatic basis of structure-function correlation in proteins , 1981 .

[42]  J. Danielsson,et al.  Folding without charges , 2012, Proceedings of the National Academy of Sciences.

[43]  Benjamin A Hall,et al.  Exploring peptide-membrane interactions with coarse-grained MD simulations. , 2011, Biophysical journal.

[44]  Ron O. Dror,et al.  Mechanism of Voltage Gating in Potassium Channels , 2012, Science.

[45]  Munehito Arai,et al.  Testing the relationship between foldability and the early folding events of dihydrofolate reductase from Escherichia coli. , 2003, Journal of molecular biology.

[46]  Werner Treptow,et al.  Intermediate states of the Kv1.2 voltage sensor from atomistic molecular dynamics simulations , 2011, Proceedings of the National Academy of Sciences.

[47]  B. García-Moreno E.,et al.  Charges in the hydrophobic interior of proteins , 2010, Proceedings of the National Academy of Sciences.

[48]  Arieh Warshel,et al.  Multiscale simulations of protein landscapes: Using coarse‐grained models as reference potentials to full explicit models , 2010, Proteins.

[49]  Arieh Warshel,et al.  Electrostatic contributions to protein stability and folding energy , 2007, FEBS letters.

[50]  D. Tieleman,et al.  The MARTINI force field: coarse grained model for biomolecular simulations. , 2007, The journal of physical chemistry. B.

[51]  E. Shakhnovich,et al.  Conserved residues and the mechanism of protein folding , 1996, Nature.

[52]  A. Warshel,et al.  Consistent Force Field Calculations. II. Crystal Structures, Sublimation Energies, Molecular and Lattice Vibrations, Molecular Conformations, and Enthalpies of Alkanes , 1970 .

[53]  P. Wolynes Recent successes of the energy landscape theory of protein folding and function , 2005, Quarterly Reviews of Biophysics.

[54]  Arieh Warshel,et al.  Paradynamics: an effective and reliable model for ab initio QM/MM free-energy calculations and related tasks. , 2011, The journal of physical chemistry. B.

[55]  Thomas Meier,et al.  Catalytic and mechanical cycles in F‐ATP synthases , 2006, EMBO reports.

[56]  Arieh Warshel,et al.  Effective approach for calculations of absolute stability of proteins using focused dielectric constants , 2009, Proteins.

[57]  Chaolin Zhang,et al.  The lncRNA Malat1 is dispensable for mouse development but its transcription plays a cis-regulatory role in the adult. , 2012, Cell reports.

[58]  Douglas J. Tobias,et al.  Arginine in Membranes: The Connection Between Molecular Dynamics Simulations and Translocon-Mediated Insertion Experiments , 2010, The Journal of Membrane Biology.

[59]  K. Swartz,et al.  Sensing voltage across lipid membranes , 2008, Nature.

[60]  Arieh Warshel,et al.  Using simplified protein representation as a reference potential for all-atom calculations of folding free energy , 1999 .

[61]  Berk Hess,et al.  3₁₀-helix conformation facilitates the transition of a voltage sensor S4 segment toward the down state. , 2011, Biophysical journal.

[62]  Gunnar von Heijne,et al.  A biphasic pulling force acts on transmembrane helices during translocon-mediated membrane integration , 2012, Nature Structural &Molecular Biology.

[63]  Lucy R. Forrest,et al.  (Pseudo-)Symmetrical Transport , 2013, Science.

[64]  Arieh Warshel,et al.  Realistic simulation of the activation of voltage-gated ion channels , 2012, Proceedings of the National Academy of Sciences.

[65]  Arieh Warshel,et al.  Realistic simulations of the coupling between the protomotive force and the mechanical rotation of the F0-ATPase , 2012, Proceedings of the National Academy of Sciences.

[66]  Gregory A Voth,et al.  A multiscale coarse-graining method for biomolecular systems. , 2005, The journal of physical chemistry. B.

[67]  M Levitt,et al.  Folding and stability of helical proteins: carp myogen. , 1976, Journal of molecular biology.

[68]  Arieh Warshel,et al.  Consistent force field for calculation of vibrational spectra and conformations of some amides and lactam rings , 1970 .

[69]  D. Laurents,et al.  pH dependence of the urea and guanidine hydrochloride denaturation of ribonuclease A and ribonuclease T1. , 1990, Biochemistry.

[70]  Arieh Warshel,et al.  Exploring, refining, and validating the paradynamics QM/MM sampling. , 2012, The journal of physical chemistry. B.

[71]  B Honig,et al.  Free-energy determinants of alpha-helix insertion into lipid bilayers. , 1996, Biophysical journal.

[72]  Kazuhiko Kinosita,et al.  Direct observation of the rotation of F1-ATPase , 1997, Nature.

[73]  A. Warshel,et al.  Electrostatic basis for enzyme catalysis. , 2006, Chemical reviews.

[74]  A. Warshel,et al.  Consistent Force Field for Calculations of Conformations, Vibrational Spectra, and Enthalpies of Cycloalkane and n‐Alkane Molecules , 1968 .

[75]  Valentina Tozzini,et al.  Coarse-grained models for proteins. , 2005, Current opinion in structural biology.

[76]  Arieh Warshel,et al.  Progress in ab initio QM/MM free-energy simulations of electrostatic energies in proteins: accelerated QM/MM studies of pKa, redox reactions and solvation free energies. , 2009, The journal of physical chemistry. B.

[77]  J. B. Matthew Electrostatic effects in proteins. , 1985, Annual review of biophysics and biophysical chemistry.

[78]  A. Fersht,et al.  Histidine-aromatic interactions in barnase. Elevation of histidine pKa and contribution to protein stability. , 1992, Journal of molecular biology.

[79]  Klaus Schulten,et al.  Molecular dynamics investigation of the ω-current in the Kv1.2 voltage sensor domains. , 2012, Biophysical journal.