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Dynamics of the Peripheral Membrane Protein P2 from Human Myelin Measured by Neutron Scattering--A Comparison between Wild-Type Protein and a Hinge Mutant.

Laulumaa S, Nieminen T, Lehtimäki M, Aggarwal S, Simons M, Koza MM, Vattulainen I, Kursula P, Natali F - PLoS ONE (2015)

Bottom Line: The P38G mutation did not change the overall structure of the protein.Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared.Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland; German Electron Synchrotron (DESY), Hamburg, Germany; European Spallation Source (ESS), Lund, Sweden.

ABSTRACT
Myelin protein P2 is a fatty acid-binding structural component of the myelin sheath in the peripheral nervous system, and its function is related to its membrane binding capacity. Here, the link between P2 protein dynamics and structure and function was studied using elastic incoherent neutron scattering (EINS). The P38G mutation, at the hinge between the β barrel and the α-helical lid, increased the lipid stacking capacity of human P2 in vitro, and the mutated protein was also functional in cultured cells. The P38G mutation did not change the overall structure of the protein. For a deeper insight into P2 structure-function relationships, information on protein dynamics in the 10 ps to 1 ns time scale was obtained using EINS. Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared. Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale. Molecular dynamics simulations confirmed the enhanced dynamics of the mutant variant, especially within the portal region in the presence of bound fatty acid. The increased softness of the hinge mutant of human myelin P2 protein is likely related to an enhanced flexibility of the portal region of this fatty acid-binding protein, as well as to its interactions with the lipid bilayer surface requiring conformational adaptations.

No MeSH data available.


Related in: MedlinePlus

Folding and dynamics of P2.(a) CD spectra of wtP2 (red) and P2-P38G (blue) in solution. Solid lines represent the samples before neutron scattering experiments and dashed lines the samples after these experiments at 293 K. Dashed dotted lines are denatured samples at 363 K. The melting curves at 201 (dashed line) and 217 nm (solid line) as a function of temperature are shown in the inset. (b) Root-mean square fluctuation (RMSF) per residue analyzed for all the four simulated systems from the final 2500 ns of the simulation trajectory. Data for P2 without palmitate are shown in black (wild type) and red (P38G mutant). The results for P2 with palmitate are depicted in green (wild type) and blue (P38G). Large RMSF values represent regions with high flexibility. The most flexible parts of the protein are found at the two loops opposing the lid. (c) A visualisation in VMD [42] of the RMS fluctuations in the P38G mutant with the palmitate chain inside the binding pocket. The yellow color corresponds to the mutated amino acid Gly38. The most flexible parts of the protein are pictured in bright magenta color. The colour bar at the bottom describes the range of RMSF values (light blue for low, violet for high).
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pone.0128954.g002: Folding and dynamics of P2.(a) CD spectra of wtP2 (red) and P2-P38G (blue) in solution. Solid lines represent the samples before neutron scattering experiments and dashed lines the samples after these experiments at 293 K. Dashed dotted lines are denatured samples at 363 K. The melting curves at 201 (dashed line) and 217 nm (solid line) as a function of temperature are shown in the inset. (b) Root-mean square fluctuation (RMSF) per residue analyzed for all the four simulated systems from the final 2500 ns of the simulation trajectory. Data for P2 without palmitate are shown in black (wild type) and red (P38G mutant). The results for P2 with palmitate are depicted in green (wild type) and blue (P38G). Large RMSF values represent regions with high flexibility. The most flexible parts of the protein are found at the two loops opposing the lid. (c) A visualisation in VMD [42] of the RMS fluctuations in the P38G mutant with the palmitate chain inside the binding pocket. The yellow color corresponds to the mutated amino acid Gly38. The most flexible parts of the protein are pictured in bright magenta color. The colour bar at the bottom describes the range of RMSF values (light blue for low, violet for high).

Mentions: wtP2 and P2-P38G have indistinguishable folding in solution as well, as shown by CD spectroscopy (Fig 2a). The melting curves for both proteins have similar trends: complete unfolding happens slowly between 310 and 350 K, the melting temperature being 331 K for wtP2 and 325 K for P2-P38G. This difference of 6 K in temperature stability is also likely to be reflected in the respective dynamics of wtP2 and P2-P38G, indirectly suggesting a more dynamic nature for the mutant protein.


Dynamics of the Peripheral Membrane Protein P2 from Human Myelin Measured by Neutron Scattering--A Comparison between Wild-Type Protein and a Hinge Mutant.

Laulumaa S, Nieminen T, Lehtimäki M, Aggarwal S, Simons M, Koza MM, Vattulainen I, Kursula P, Natali F - PLoS ONE (2015)

Folding and dynamics of P2.(a) CD spectra of wtP2 (red) and P2-P38G (blue) in solution. Solid lines represent the samples before neutron scattering experiments and dashed lines the samples after these experiments at 293 K. Dashed dotted lines are denatured samples at 363 K. The melting curves at 201 (dashed line) and 217 nm (solid line) as a function of temperature are shown in the inset. (b) Root-mean square fluctuation (RMSF) per residue analyzed for all the four simulated systems from the final 2500 ns of the simulation trajectory. Data for P2 without palmitate are shown in black (wild type) and red (P38G mutant). The results for P2 with palmitate are depicted in green (wild type) and blue (P38G). Large RMSF values represent regions with high flexibility. The most flexible parts of the protein are found at the two loops opposing the lid. (c) A visualisation in VMD [42] of the RMS fluctuations in the P38G mutant with the palmitate chain inside the binding pocket. The yellow color corresponds to the mutated amino acid Gly38. The most flexible parts of the protein are pictured in bright magenta color. The colour bar at the bottom describes the range of RMSF values (light blue for low, violet for high).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4466134&req=5

pone.0128954.g002: Folding and dynamics of P2.(a) CD spectra of wtP2 (red) and P2-P38G (blue) in solution. Solid lines represent the samples before neutron scattering experiments and dashed lines the samples after these experiments at 293 K. Dashed dotted lines are denatured samples at 363 K. The melting curves at 201 (dashed line) and 217 nm (solid line) as a function of temperature are shown in the inset. (b) Root-mean square fluctuation (RMSF) per residue analyzed for all the four simulated systems from the final 2500 ns of the simulation trajectory. Data for P2 without palmitate are shown in black (wild type) and red (P38G mutant). The results for P2 with palmitate are depicted in green (wild type) and blue (P38G). Large RMSF values represent regions with high flexibility. The most flexible parts of the protein are found at the two loops opposing the lid. (c) A visualisation in VMD [42] of the RMS fluctuations in the P38G mutant with the palmitate chain inside the binding pocket. The yellow color corresponds to the mutated amino acid Gly38. The most flexible parts of the protein are pictured in bright magenta color. The colour bar at the bottom describes the range of RMSF values (light blue for low, violet for high).
Mentions: wtP2 and P2-P38G have indistinguishable folding in solution as well, as shown by CD spectroscopy (Fig 2a). The melting curves for both proteins have similar trends: complete unfolding happens slowly between 310 and 350 K, the melting temperature being 331 K for wtP2 and 325 K for P2-P38G. This difference of 6 K in temperature stability is also likely to be reflected in the respective dynamics of wtP2 and P2-P38G, indirectly suggesting a more dynamic nature for the mutant protein.

Bottom Line: The P38G mutation did not change the overall structure of the protein.Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared.Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland; German Electron Synchrotron (DESY), Hamburg, Germany; European Spallation Source (ESS), Lund, Sweden.

ABSTRACT
Myelin protein P2 is a fatty acid-binding structural component of the myelin sheath in the peripheral nervous system, and its function is related to its membrane binding capacity. Here, the link between P2 protein dynamics and structure and function was studied using elastic incoherent neutron scattering (EINS). The P38G mutation, at the hinge between the β barrel and the α-helical lid, increased the lipid stacking capacity of human P2 in vitro, and the mutated protein was also functional in cultured cells. The P38G mutation did not change the overall structure of the protein. For a deeper insight into P2 structure-function relationships, information on protein dynamics in the 10 ps to 1 ns time scale was obtained using EINS. Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared. Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale. Molecular dynamics simulations confirmed the enhanced dynamics of the mutant variant, especially within the portal region in the presence of bound fatty acid. The increased softness of the hinge mutant of human myelin P2 protein is likely related to an enhanced flexibility of the portal region of this fatty acid-binding protein, as well as to its interactions with the lipid bilayer surface requiring conformational adaptations.

No MeSH data available.


Related in: MedlinePlus