Gene

Amino acid residue

Quantum mechanics

Structural rigidity

Chemical physics

Amino acid

Biology

Materials science

Nuclear magnetic resonance

Biochemistry

Protein structure

Rigidity (electromagnetism)

Physics

Protein secondary structure

Mathematics

Molecular dynamics

Geometry

Crystallography

Chemistry

Biological system

Biophysics

Peptide sequence

Biophysical Journal

Complementary neutron- and light-scattering results on nine proteins and amino acids reveal the role of rigidity and secondary structure in determining the time- and lengthscales of low-frequency collective vibrational dynamics in proteins. These dynamics manifest in a spectral feature, known as the boson peak (BP), which is common to all disordered materials. We demonstrate that BP position scales systematically with structural motifs, reflecting local rigidity: disordered proteins appear softer than α-helical proteins; which are softer than β-sheet proteins. Our analysis also reveals a universal spectral shape of the BP in proteins and amino acid mixtures; superimposable on the shape observed in typical glasses. Uniformity in the underlying physical mechanism, independent of the specific chemical composition, connects the BP vibrations to nanometer-scale heterogeneities, providing an experimental benchmark for coarse-grained simulations, structure/rigidity relationships, and engineering of proteins for novel applications.

Rigidity, Secondary Structure, and the Universality of the Boson Peak in Proteins