A novel molecular dynamics approach to evaluate the effect of phosphorylation on multimeric protein interface: the αB-Crystallin case study

Abstract

BackgroundPhosphorylation is one of the most important post-translational modifications (PTM) employed by cells to regulate several cellular processes. Studying the effects of phosphorylations on protein structures allows to investigate the modulation mechanisms of several proteins including chaperones, like the small HSPs, which display different multimeric structures according to the phosphorylation of a few serine residues. In this context, the proposed study is aimed at finding a method to correlate different PTM patterns (in particular phosphorylations at the monomers interface of multimeric complexes) with the dynamic behaviour of the complex, using physicochemical parameters derived from molecular dynamics simulations in the timescale of nanoseconds.ResultsWe have developed a methodology relying on computing nine physicochemical parameters, derived from the analysis of short MD simulations, and combined with N identifiers that characterize the PTMs of the analysed protein. The nine general parameters were validated on three proteins, with known post-translational modified conformation and unmodified conformation. Then, we applied this approach to the case study of αB-Crystallin, a chaperone which multimeric state (up to 40 units) is supposed to be controlled by phosphorylation of Ser45 and Ser59. Phosphorylation of serines at the dimer interface induces the release of hexamers, the active state of αB-Crystallin. 30 ns of MD simulation were obtained for each possible combination of dimer phosphorylation state and average values of structural, dynamic, energetic and functional features were calculated on the equilibrated portion of the trajectories. Principal Component Analysis was applied to the parameters and the first five Principal Components, which summed up to 84 % of the total variance, were finally considered.ConclusionsThe validation of this approach on multimeric proteins, which structures were known both modified and unmodified, allowed us to propose a new approach that can be used to predict the impact of PTM patterns in multi-modified proteins using data collected from short molecular dynamics simulations. Analysis on the αB-Crystallin case study clusters together all-P dimers with all-P hexamers and no-P dimer with no-P hexamer and results suggest a great influence of Ser59 phosphorylation on chain B.

Association of Alpha-Crystallin with Fiber Cell Plasma Membrane of the Eye Lens Accompanied by Light Scattering and Cataract Formation

“…Phosphorylation changes the protein's surface charge, accompanied by conformational changes, which may change the protein-protein interaction and reduce the chaperone function [227]. Chiappori et al [255] modeled dimers and hexamers from the 24-meric structure of αBcrystallin (PDB id: 2YGD) and performed the molecular dynamics (MD) simulation studies with all Ser 45/Ser 59 phosphorylated and all non-phosphorylated forms. Their simulation studies [255] suggest that Ser 59 is a key residue for regulating the multimeric conformation of αB-crystallin.…”

Mass Spectrometry-Based Characterization of the Virion Proteome, Phosphoproteome, and Associated Kinase Activity of Human Cytomegalovirus

“…It was notably shown to decorate three-quarters of the detected proteins in human cells to various degrees [73]. A major role played by phosphorylation is intervening in the stabilization or destabilization of protein-protein interactions [74][75][76][77][78][79]. Therefore, the knowledge on the phosphorylation status of HCMV virion proteins may help in understanding how this particular PTM influences the assembly and stability of this multiprotein system.…”

Effects of Acetylation and Phosphorylation on Subunit Interactions in Three Large Eukaryotic Complexes

“…Their conclusions were of qualitative nature, for instance they observed the reorientation of proteins, formation and breaking of salt bridges and hydrogen bonds in the respective complexes. Additionally, an MDbased method employing nine physicochemical parameters extracted from the trajectories was recently proposed to predict the impact of phosphorylation on protein-protein interactions (21).…”