Extension of the UNRES Coarse-Grained Force Field to Membrane Proteins in the Lipid Bilayer

2019 ◽  
Vol 123 (37) ◽  
pp. 7829-7839
Author(s):  
Karolina Ziȩba ◽  
Magdalena Ślusarz ◽  
Rafał Ślusarz ◽  
Adam Liwo ◽  
Cezary Czaplewski ◽  
...  
2017 ◽  
Author(s):  
Ronald D Hills, Jr

Coarse-grained simulations enable the study of membrane proteins in the context of their native environment but require reliable parameters. The CgProt force field is assessed by comparing the potentials of mean force for sidechain insertion in a DOPC bilayer to results reported for atomistic molecular dynamics simulations. The reassignment of polar sidechain sites was found to improve the attractive interfacial behavior of tyrosine, phenylalanine and asparagine as well as charged lysine and arginine residues. The solvation energy at membrane depths of 0, 1.3 and 1.7 nm correlate with experimental partition coefficients in aqueous mixtures of cyclohexane, octanol and POPC, respectively, for sidechain analogs and Wimley-White peptides. These data points can be used to further discriminate between alternate force field parameters. Available partitioning data was also used to reparameterize the representation of the polar peptide backbone for non-alanine residues. The newly developed force field, CgProt 2.4, correctly predicts the global energy minimum in the potentials of mean force for insertion of the uncharged membrane-associated peptides LS3 and WALP23. CgProt will find application in molecular dynamics simulations of a variety of membrane protein systems.


2021 ◽  
Author(s):  
Christos Lamprakis ◽  
Ioannis Andreadelis ◽  
John Manchester ◽  
Camilo Velez-Vega ◽  
José S. Duca ◽  
...  

<p>Protein-protein complex assembly is one of the major drivers of biological response. Understanding the mechanisms of protein oligomerization/dimerization would allow one to elucidate how these complexes participate in biological activities and could ultimately lead to new approaches in designing novel therapeutic agents. However, determining the exact association pathways and structures of such complexes remains a challenge. Here, we use parallel tempering metadynamics simulations in the well-tempered ensemble to evaluate the performance of Martini 2.2P and Martini open-beta 3 (Martini 3) force fields in reproducing the structure and energetics of the dimerization process of membrane proteins and proteins in an aqueous solution in reasonable accuracy and throughput. We find that Martini 2.2P systematically overestimates the free energy of association by estimating large barriers in distinct areas, which likely leads to overaggregation when multiple monomers are present. In comparison, the less viscous Martini 3 results in a systematic underestimation of the free energy of association for proteins in solution, while it performs well in describing the association of membrane proteins. In all cases the near-native dimer complexes are identified as minima in the free energy surface albeit not always as the lowest minima. In the case of Martini 3 we find that the spurious supramolecular protein aggregation present in Martini 2.2P multimer simulations is alleviated and thus this force field may be more suitable for the study of protein oligomerization. We propose that the use of enhanced sampling simulations with a refined coarse-grained force field and appropriately defined collective variables is a robust approach for studying the protein dimerization process, although one should be cautious of the ranking of energy minima.</p>


2008 ◽  
Vol 36 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Mark S.P. Sansom ◽  
Kathryn A. Scott ◽  
Peter J. Bond

An understanding of the interactions of membrane proteins with a lipid bilayer environment is central to relating their structure to their function and stability. A high-throughput approach to prediction of membrane protein interactions with a lipid bilayer based on coarse-grained Molecular Dynamics simulations is described. This method has been used to develop a database of CG simulations (coarse-grained simulations) of membrane proteins (http://sbcb.bioch.ox.ac.uk/cgdb). Comparison of CG simulations and AT simulations (atomistic simulations) of lactose permease reveals good agreement between the two methods in terms of predicted lipid headgroup contacts. Both CG and AT simulations predict considerable local bilayer deformation by the voltage sensor domain of the potassium channel KvAP.


2014 ◽  
Vol 10 (8) ◽  
pp. 3459-3472 ◽  
Author(s):  
Parimal Kar ◽  
Srinivasa Murthy Gopal ◽  
Yi-Ming Cheng ◽  
Afra Panahi ◽  
Michael Feig

2021 ◽  
Author(s):  
Christos Lamprakis ◽  
Ioannis Andreadelis ◽  
John Manchester ◽  
Camilo Velez-Vega ◽  
José S. Duca ◽  
...  

<p>Protein-protein complex assembly is one of the major drivers of biological response. Understanding the mechanisms of protein oligomerization/dimerization would allow one to elucidate how these complexes participate in biological activities and could ultimately lead to new approaches in designing novel therapeutic agents. However, determining the exact association pathways and structures of such complexes remains a challenge. Here, we use parallel tempering metadynamics simulations in the well-tempered ensemble to evaluate the performance of Martini 2.2P and Martini open-beta 3 (Martini 3) force fields in reproducing the structure and energetics of the dimerization process of membrane proteins and proteins in an aqueous solution in reasonable accuracy and throughput. We find that Martini 2.2P systematically overestimates the free energy of association by estimating large barriers in distinct areas, which likely leads to overaggregation when multiple monomers are present. In comparison, the less viscous Martini 3 results in a systematic underestimation of the free energy of association for proteins in solution, while it performs well in describing the association of membrane proteins. In all cases the near-native dimer complexes are identified as minima in the free energy surface albeit not always as the lowest minima. In the case of Martini 3 we find that the spurious supramolecular protein aggregation present in Martini 2.2P multimer simulations is alleviated and thus this force field may be more suitable for the study of protein oligomerization. We propose that the use of enhanced sampling simulations with a refined coarse-grained force field and appropriately defined collective variables is a robust approach for studying the protein dimerization process, although one should be cautious of the ranking of energy minima.</p>


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4230 ◽  
Author(s):  
Ronald D. Hills, Jr

Coarse-grained (CG) models have been successful in simulating the chemical properties of lipid bilayers, but accurate treatment of membrane proteins and lipid-protein molecular interactions remains a challenge. The CgProt force field, original developed with the multiscale coarse graining method, is assessed by comparing the potentials of mean force for sidechain insertion in a DOPC bilayer to results reported for atomistic molecular dynamics simulations. Reassignment of select CG sidechain sites from the apolar to polar site type was found to improve the attractive interfacial behavior of tyrosine, phenylalanine and asparagine as well as charged lysine and arginine residues. The solvation energy at membrane depths of 0, 1.3 and 1.7 nm correlates with experimental partition coefficients in aqueous mixtures of cyclohexane, octanol and POPC, respectively, for sidechain analogs and Wimley-White peptides. These experimental values serve as important anchor points in choosing between alternate CG models based on their observed permeation profiles, particularly for Arg, Lys and Gln residues where the all-atom OPLS solvation energy does not agree well with experiment. Available partitioning data was also used to reparameterize the representation of the peptide backbone, which needed to be made less attractive for the bilayer hydrophobic core region. The newly developed force field, CgProt 2.4, correctly predicts the global energy minimum in the potentials of mean force for insertion of the uncharged membrane-associated peptides LS3 and WALP23. CgProt will find application in studies of lipid-protein interactions and the conformational properties of diverse membrane protein systems.


2017 ◽  
Author(s):  
Ronald D Hills, Jr

Coarse-grained simulations enable the study of membrane proteins in the context of their native environment but require reliable parameters. The CgProt force field is assessed by comparing the potentials of mean force for sidechain insertion in a DOPC bilayer to results reported for atomistic molecular dynamics simulations. The reassignment of polar sidechain sites was found to improve the attractive interfacial behavior of tyrosine, phenylalanine and asparagine as well as charged lysine and arginine residues. The solvation energy at membrane depths of 0, 1.3 and 1.7 nm correlate with experimental partition coefficients in aqueous mixtures of cyclohexane, octanol and POPC, respectively, for sidechain analogs and Wimley-White peptides. These data points can be used to further discriminate between alternate force field parameters. Available partitioning data was also used to reparameterize the representation of the polar peptide backbone for non-alanine residues. The newly developed force field, CgProt 2.4, correctly predicts the global energy minimum in the potentials of mean force for insertion of the uncharged membrane-associated peptides LS3 and WALP23. CgProt will find application in molecular dynamics simulations of a variety of membrane protein systems.


2005 ◽  
Vol 33 (5) ◽  
pp. 910-912 ◽  
Author(s):  
P.J. Bond ◽  
J. Cuthbertson ◽  
M.S.P. Sansom

Interactions between membrane proteins and detergents are important in biophysical and structural studies and are also biologically relevant in the context of folding and transport. Despite a paucity of high-resolution data on protein–detergent interactions, novel methods and increased computational power enable simulations to provide a means of understanding such interactions in detail. Simulations have been used to compare the effect of lipid or detergent on the structure and dynamics of membrane proteins. Moreover, some of the longest and most complex simulations to date have been used to observe the spontaneous formation of membrane protein–detergent micelles. Common mechanistic steps in the micelle self-assembly process were identified for both α-helical and β-barrel membrane proteins, and a simple kinetic mechanism was proposed. Recently, simplified (i.e. coarse-grained) models have been utilized to follow long timescale transitions in membrane protein–detergent assemblies.


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