scholarly journals Electrostatics in the stability and misfolding of the prion protein: salt bridges, self energy, and solvationThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.

2010 ◽  
Vol 88 (2) ◽  
pp. 371-381 ◽  
Author(s):  
Will C. Guest ◽  
Neil R. Cashman ◽  
Steven S. Plotkin
Keyword(s):  
Prion Protein ◽  
Electrostatic Potential ◽  
Peer Review Process ◽  
Salt Bridge ◽  
Salt Bridges ◽  
Self Energy ◽  
Low Dielectric ◽  
The Stability ◽  
Α Helix ◽  
Electrostatic Potential Energy

Using a recently developed mesoscopic theory of protein dielectrics, we have calculated the salt bridge energies, total residue electrostatic potential energies, and transfer energies into a low dielectric amyloid-like phase for 12 species and mutants of the prion protein. Salt bridges and self energies play key roles in stabilizing secondary and tertiary structural elements of the prion protein. The total electrostatic potential energy of each residue was found to be invariably stabilizing. Residues frequently found to be mutated in familial prion disease were among those with the largest electrostatic energies. The large barrier to charged group desolvation imposes regional constraints on involvement of the prion protein in an amyloid aggregate, resulting in an electrostatic amyloid recruitment profile that favours regions of sequence between α helix 1 and β strand 2, the middles of helices 2 and 3, and the region N-terminal to α helix 1. We found that the stabilization due to salt bridges is minimal among the proteins studied for disease-susceptible human mutants of prion protein.

Investigation on salt bridge interactions of mammalian prion proteins by molecular dynamics simulation / Memeli prion proteinlerinin moleküler dinamik simulasyon ile tuz köprüleri etkileşimlerinin araştırılması

2016 ◽  
Vol 41 (3) ◽  
Author(s):  
Xiliang Chen ◽  
Xin Chen ◽  
Yafang Liu
Keyword(s):  
Molecular Dynamics ◽  
Prion Protein ◽  
Electrostatic Interactions ◽  
Prion Proteins ◽  
Salt Bridge ◽  
Dynamics Simulation ◽  
Salt Bridges ◽  
Tertiary Structures ◽  
Local Structures ◽  
The Stability

AbstractObjective: Salt bridge interaction is one of the most important electrostatic interactions to stabilize the secondary and tertiary structures of protein. To obtain more insight into the molecular basis of prion proteins, the salt bridge networks in two animal prion proteins are studied in this work.Methods: Molecular dynamics (MD) and Flow MD (FMD) simulations are employed to investigate the salt bridges interactions of rabbit prion protein (rPrPc), Syrian hamster prion protein (syPrPc) and the variants of the two prion proteins.Results: The dynamic behaviors of salt bridges are characterized, and the relation between salt bridge interactions and local structures are also discussed. The type of salt bridges in the two prion proteins is divided into the helixloop, intra-helix and inter-helix salt bridges. It is found that the helix-loop salt bridges is more important for the stability of prion proteins than the other two kinds of slat bridge.Conclusion: The Asp201-Arg155 (rS1), Asp177-Arg163 (rS3) and Asp178-Arg164 (syS1) are the important salt bridges to stabilize the structures of rPrPc and syPrPc, respectively. The structural stability is partly depended on the number of helix-loop salt bridge.

scholarly journals How well do force fields capture the strength of salt bridges in proteins?

2018 ◽  
Author(s):  
Mustapha Carab Ahmed ◽  
Elena Papaleo ◽  
Kresten Lindorff-Larsen
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Force Fields ◽  
Salt Bridge ◽  
Salt Bridges ◽  
Enhanced Sampling ◽  
Important Interaction ◽  
Close Proximity ◽  
The Stability ◽  
Dynamics Simulations

AbstractSalt bridges form between pairs of ionisable residues in close proximity and are important interactions in proteins. While salt bridges are known to be important both for protein stability, recognition and regulation, we still do not have fully accurate predictive models to assess the energetic contributions of salt bridges. Molecular dynamics simulations is one technique that may be used study the complex relationship between structure, solvation and energetics of salt bridges, but the accuracy of such simulations depend on the force field used. We have used NMR data on the B1 domain of protein G (GB1) to benchmark molecular dynamics simulations. Using enhanced sampling simulations, we calculated the free energy of forming a salt bridge for three possible ionic interactions in GB1. The NMR experiments showed that these interactions are either not formed, or only very weakly formed, in solution. In contrast, we show that the stability of the salt bridges is slightly overestimated in simulations of GB1 using six commonly used combinations of force fields and water models. We therefore conclude that further work is needed to refine our ability to model quantitatively the stability of salt bridges through simulations, and that comparisons between experiments and simulations will play a crucial role in furthering our understanding of this important interaction.

Insights into stabilizing interactions in the distorted domain-swapped dimer ofSalmonella typhimuriumsurvival protein

2015 ◽  
Vol 71 (9) ◽  
pp. 1812-1823 ◽  
Author(s):  
Yamuna Kalyani Mathiharan ◽  
H. S. Savithri ◽  
M. R. N. Murthy
Keyword(s):  
Hydrogen Bond ◽  
Catalytic Activity ◽  
Salt Bridge ◽  
Salt Bridges ◽  
X Ray ◽  
Dimeric Interface ◽  
Distorted Structure ◽  
Dimeric Protein ◽  
The Stability

The survival protein SurE fromSalmonella typhimurium(StSurE) is a dimeric protein that functions as a phosphatase. SurE dimers are formed by the swapping of a loop with a pair of β-strands and a C-terminal helix between two protomers. In a previous study, the Asp230 and His234 residues were mutated to Ala to abolish a hydrogen bond that was thought to be crucial for C-terminal helix swapping. These mutations led to functionally inactive and distorted dimers in which the two protomers were related by a rotation of 167°. New salt bridges involving Glu112 were observed in the dimeric interface of the H234A and D230A/H234A mutants. To explore the role of these salt bridges in the stability of the distorted structure, E112A, E112A/D230A, E112A/H234A, E112A/D230A/H234A, R179L/H180A/H234A and E112A/R179L/H180A/H234A mutants were constructed. X-ray crystal structures of the E112A, E112A/H234A and E112A/D230A mutants could be determined. The dimeric structures of the E112A and E112A/H234A mutants were similar to that of native SurE, while the E112A/D230A mutant had a residual rotation of 11° between theBchains upon superposition of theAchains of the mutant and native dimers. The native dimeric structure was nearly restored in the E112A/H234A mutant, suggesting that the new salt bridge observed in the H234A and D230A/H234A mutants was indeed responsible for the stability of their distorted structures. Catalytic activity was also restored in these mutants, implying that appropriate dimeric organization is necessary for the activity of SurE.

scholarly journals Intrinsic basis of thermostability of prolyl oligopeptidase from Pyrococcus furiosus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahini Banerjee ◽  
Parth Sarthi Sen Gupta ◽  
Rifat Nawaz Ul Islam ◽  
Amal Kumar Bandyopadhyay
Keyword(s):  
Pyrococcus Furiosus ◽  
Intrinsic Property ◽  
Salt Bridge ◽  
Primary Role ◽  
Salt Bridges ◽  
Energy Contribution ◽  
Desolvation Energy ◽  
The Stability ◽  
Intrinsic Basis

AbstractSalt-bridges play a key role in the thermostability of proteins adapted in stress environments whose intrinsic basis remains to be understood. We find that the higher hydrophilicity of PfP than that of HuP is due to the charged but not the polar residues. The primary role of these residues is to enhance the salt-bridges and their ME. Unlike HuP, PfP has made many changes in its intrinsic property to strengthen the salt-bridge. First, the desolvation energy is reduced by directing the salt-bridge towards the surface. Second, it has made bridge-energy more favorable by recruiting energetically advantageous partners with high helix-propensity among the six possible salt-bridge pairs. Third, ME-residues that perform intricate interactions have increased their energy contribution by making major changes in their binary properties. The use of salt-bridge partners as ME-residues, and ME-residues' overlapping usage, predominant in helices, and energetically favorable substitution are some of the favorable features of PfP compared to HuP. These changes in PfP reduce the unfavorable, increase the favorable ME-energy. Thus, the per salt-bridge stability of PfP is greater than that of HuP. Further, unfavorable target ME-residues can be identified whose mutation can increase the stability of salt-bridge. The study applies to other similar systems.

scholarly journals How well do force fields capture the strength of salt bridges in proteins?

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4967 ◽  
Author(s):  
Mustapha Carab Ahmed ◽  
Elena Papaleo ◽  
Kresten Lindorff-Larsen
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Force Fields ◽  
Salt Bridge ◽  
Dynamics Simulation ◽  
Ionic Interactions ◽  
Salt Bridges ◽  
Important Interaction ◽  
The Stability ◽  
Dynamics Simulations

Salt bridges form between pairs of ionisable residues in close proximity and are important interactions in proteins. While salt bridges are known to be important both for protein stability, recognition and regulation, we still do not have fully accurate predictive models to assess the energetic contributions of salt bridges. Molecular dynamics simulation is one technique that may be used study the complex relationship between structure, solvation and energetics of salt bridges, but the accuracy of such simulations depends on the force field used. We have used NMR data on the B1 domain of protein G (GB1) to benchmark molecular dynamics simulations. Using enhanced sampling simulations, we calculated the free energy of forming a salt bridge for three possible lysine-carboxylate ionic interactions in GB1. The NMR experiments showed that these interactions are either not formed, or only very weakly formed, in solution. In contrast, we show that the stability of the salt bridges is overestimated, to different extents, in simulations of GB1 using seven out of eight commonly used combinations of fixed charge force fields and water models. We also find that the Amber ff15ipq force field gives rise to weaker salt bridges in good agreement with the NMR experiments. We conclude that many force fields appear to overstabilize these ionic interactions, and that further work may be needed to refine our ability to model quantitatively the stability of salt bridges through simulations. We also suggest that comparisons between NMR experiments and simulations will play a crucial role in furthering our understanding of this important interaction.

scholarly journals The Role of Helix 1 Aspartates and Salt Bridges in the Stability and Conversion of Prion Protein

2003 ◽  
Vol 278 (14) ◽  
pp. 12522-12529 ◽  
Author(s):  
Jonathan O. Speare ◽  
Thomas S. Rush ◽  
Marshall E. Bloom ◽  
Byron Caughey
Keyword(s):  
Prion Protein ◽  
Salt Bridges ◽  
The Stability

scholarly journals Revisiting the valence stability and preparation of perovskite structure type oxides ABO3 with the use of Madelung electrostatic potential energy and lattice site potential

RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 20737-20745
Author(s):  
Masahiro Yoshimura ◽  
Kripasindhu Sardar
Keyword(s):  
Potential Energy ◽  
Electrostatic Potential ◽  
Valence State ◽  
Perovskite Structure ◽  
Lattice Site ◽  
Structure Type ◽  
The Stability ◽  
Electrostatic Potential Energy

The stability of perovskite structure type oxides and higth valence state of cations, respectively may be better understood by considering lattice site potential and Madelung electrostatic potential energy.

MOLECULAR DYNAMIC SIMULATION OF V176G MUTATION ASSOCIATED WITH GERSTMANN–STRÄUSSLER–SCHEINKER AT ELEVATED TEMPERATURE

2016 ◽  
Vol 78 (2) ◽  
Author(s):  
Ashraf Fadhil Jomah ◽  
Mohd Shahir Shamsir
Keyword(s):  
Hydrogen Bonds ◽  
Prion Protein ◽  
Novel Mutation ◽  
Solvent Accessibility ◽  
Transmissible Spongiform Encephalopathy ◽  
Salt Bridge ◽  
Cellular Prion Protein ◽  
Spongiform Encephalopathy ◽  
Α Helix ◽  
Dynamics Simulations

The transformation of cellular prion protein (PrPc) into pathogenic conformer (PrPSc) in transmissible spongiform encephalopathy is expedited by mutations in the prion protein. One recently reported novel mutation V176G is located in region of the protein known to cause Creutzfeldt-Jakob disease (CJD) but possess a unique neuropathological profile and spongiform alteration similar to Gerstmann–Sträussler–Scheinker syndrome (GSS). Using molecular dynamics simulations; the denaturation of the prion structure with V176G at 500K was studied to identify the dynamics in structural properties such as salt bridge, solvent accessibility, hydrogen bonds and hydrophobicity. The simulations revealed that the heat-induced unfolding caused destabilization of the native structure of PrP and affecting the β-sheet region of the structure more than the α-helix. Unique salt bridge formation suggests conformational orientation that may be attributed to the V176G mutation. The mutation effects showed an increased fluctuation of the H1 region, gain of hydrogen bonds between H3 and H2 which may be part of the oligomerization pathway and determine the features of the PrPSc assemblies.

scholarly journals Salt-Bridges in the Microenvironment of Stable Protein Structures

2020 ◽  
Vol 16 (11) ◽  
pp. 900-909
Author(s):  
Amal Kumar Bandyopadhyay ◽  
Keyword(s):  
Protein Structures ◽  
Salt Bridge ◽  
Homology Model ◽  
Net Energy ◽  
Salt Bridges ◽  
Site Specific ◽  
The Core ◽  
Polar Residues ◽  
The Stability

Salt-bridges (sb) play an important role in the folding and stability of proteins. This is deduced from the evaluation of net energy in the microenvironments (ME, residues that are 4Å away from positive and negative partners of salt-bridge and interact with them). ME’s act as a determinant of net-energy due to the intrinsic features by the sequence. The stability of extremophilic proteins is due to the presence of favorable residues at the ME without any unfavorable residues. We studied a dataset of four structures from the pdb and a homology model (PDB ID: 1HM5) to gain insights on this issue. Data shows that the presence of isolated charges and polar residues in the core of extremophilic proteins helps in the formation of stable salt-bridges with reduced desolvation. Thus, site-specific mutations with favorable residues at the ME will help develop thermo stable proteins with strong salt bridges.

scholarly journals Rational thermostabilisation of four-helix bundle dimeric de novo proteins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shin Irumagawa ◽  
Kaito Kobayashi ◽  
Yutaka Saito ◽  
Takeshi Miyata ◽  
Mitsuo Umetsu ◽  
...  
Keyword(s):  
Protein Design ◽  
De Novo ◽  
Protein Complexes ◽  
Salt Bridge ◽  
Dynamics Simulation ◽  
Saturation Mutagenesis ◽  
Helix Bundle ◽  
Stable Mutant ◽  
Four Helix Bundle ◽  
The Stability

AbstractThe stability of proteins is an important factor for industrial and medical applications. Improving protein stability is one of the main subjects in protein engineering. In a previous study, we improved the stability of a four-helix bundle dimeric de novo protein (WA20) by five mutations. The stabilised mutant (H26L/G28S/N34L/V71L/E78L, SUWA) showed an extremely high denaturation midpoint temperature (Tm). Although SUWA is a remarkably hyperstable protein, in protein design and engineering, it is an attractive challenge to rationally explore more stable mutants. In this study, we predicted stabilising mutations of WA20 by in silico saturation mutagenesis and molecular dynamics simulation, and experimentally confirmed three stabilising mutations of WA20 (N22A, N22E, and H86K). The stability of a double mutant (N22A/H86K, rationally optimised WA20, ROWA) was greatly improved compared with WA20 (ΔTm = 10.6 °C). The model structures suggested that N22A enhances the stability of the α-helices and N22E and H86K contribute to salt-bridge formation for protein stabilisation. These mutations were also added to SUWA and improved its Tm. Remarkably, the most stable mutant of SUWA (N22E/H86K, rationally optimised SUWA, ROSA) showed the highest Tm (129.0 °C). These new thermostable mutants will be useful as a component of protein nanobuilding blocks to construct supramolecular protein complexes.

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