Effect of macromolecular crowding on protein binding stability: modest stabilization and significant biological consequences.

ABSTRACT: Macromolecular crowding has long been known to significantly affect protein oligomerization, and yet no direct quantitative measurements appear to have been made of its effects on the binding free energy of the elemental step of adding a single subunit. Here, we report the effects of two crowding agents on the binding free energy of two subunits in the Escherichia coli polymerase III holoenzyme. The crowding agents are found, paradoxically, to have only a modest stabilizing effect, of the order of 1 kcal/mol, on the binding of the two subunits. Systematic variations in the level of stabilization with crowder size are nevertheless observed. The data are consistent with theoretical predictions based on atomistic modeling of excluded-volume interactions with crowders. We reconcile the apparen

SUBMITTER: Batra J 

PROVIDER: S-EPMC2718143 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature