Temperature-Dependent Rotation of Protonated Methyl Groups in Otherwise Deuterated Proteins Modulates DEER Distance Distributions.

ABSTRACT: Temperature-dependent DEER effects are observed as a function of methyl rotation by either leucine- or nitroxide-specific protonated methyl groups in an otherwise deuterated background. Both species induce a site-specific enhancement in the apparent T _m relaxation of the paramagnetic nitroxide label. The presence of a single protonated methyl group in close proximity (4-10 Å) to only one of the two nitroxide rotamer ensembles in AviTagged immunoglobulin-binding B domain of protein A results in a selective and substantial decrease in T _m, manifested by differential decay of the peak intensities in the bimodal P(r) distance distribution as a function of the total dipolar evolution time, temperature, or both. The temperature-dependent differential de

SUBMITTER: Schmidt T 

PROVIDER: S-EPMC11775055 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature