Inherent dynamics of maltose binding protein (MBP) are immune to the native environment.

Abstract

Biophysical characterizations of proteins typically rely on a reductionistic approach, studying proteins in a highly purified from and in absence of their natural cellular environment. Little is known about how the highly crowded conditions prevalent within living cells influence the dynamic structures proteins on the molecular level. To address this outstanding question, we characterize here the dynamic behavior of the periplasmic model protein MBP from Escherichia coli in situ, confined in the native lumen of bacterial outer membrane vesicles. To this end we determine the dynamics of side-chain methyl groups of MBP across several timescales and compare them to purified in vitro MBP. We find that the inherent dynamics of MBP are surprisingly insensitive to the native cellular environment and that the molecular motion of the protein is mainly impacted on a global level.