From Homodimer to Heterodimer and Back: Elucidating the TonB Energy Transduction Cycle.

ABSTRACT:

Unlabelled

The TonB system actively transports large, scarce, and important nutrients through outer membrane (OM) transporters of Gram-negative bacteria using the proton gradient of the cytoplasmic membrane (CM). In Escherichia coli, the CM proteins ExbB and ExbD harness and transfer proton motive force energy to the CM protein TonB, which spans the periplasmic space and cyclically binds OM transporters. TonB has two activity domains: the amino-terminal transmembrane domain with residue H20 and the periplasmic carboxy terminus, through which it binds to OM transporters. TonB is inactivated by all substitutions at residue H20 except H20N. Here, we show that while TonB trapped as a homodimer through its amino-terminal domain retained full activity, trapping TonB through its carboxy t

SUBMITTER: Gresock MG 

PROVIDER: S-EPMC4621073 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature