Universality of Vibrational Spectra of Globular Proteins

TL;DR

This study demonstrates that the vibrational spectra of globular proteins are universal across different proteins, even in high-frequency ranges, and highlights the implications for modeling and analyzing protein dynamics.

Contribution

It provides extensive evidence of spectral universality in globular proteins using a large dataset and full atomic potential, extending previous findings to high-frequency ranges.

Findings

Vibrational spectra follow a universal curve across proteins

Spectral fluctuations reveal outliers and structural deviations

Model quality can be assessed through spectral universality

Abstract

It is shown that the density of modes of the vibrational spectrum of globular proteins is universal, i.e., regardless of the protein in question it closely follows one universal curve. The present study, including 135 proteins analyzed with a full atomic empirical potential (CHARMM22) and using the full complement of all atoms Cartesian degrees of freedom, goes far beyond previous claims of universality, confirming that universality holds even in the high-frequency range (300- 4000 1/cm), where peaks and turns in the density of states are faithfully reproduced from one protein to the next. We also characterize fluctuations of the spectral density from the average, paving the way to a meaningful discussion of rare, unusual spectra and the structural reasons for the deviations in such "outlier" proteins. Since the method used for the derivation of the vibrational modes (potential energy formulation, set of degrees of freedom employed, etc.) has a dramatic effect on the spectral density, another significant implication of our findings is that the universality can provide an exquisite tool for assessing and improving the quality of various models used for NMA computations. Finally, we show that the input configuration too affects the density of modes, thus emphasizing the importance of simplified potential energy formulations that are minimized at the outset.