Investigation of Role of Eleven TonB Homologs in Carbohydrate Utilization by Bacteroides thetaiotaomicron

ABSTRACT: Key conserved features of these transporters include a 22 beta-strand barrel that traverses the outer membrane and houses a plug domain that occludes solute passage until the transporter is activated. Some B. theta TBDTs are also predicted to include two additional domains termed the N-terminal extension (NTE) and the Secretin and TonB N-terminus (STN) domain. The precise rearrangement of the plug domain to allow solute passage through the barrel is poorly understood but is facilitated by pairing to an inner membrane complex that harnesses proton motive force. This complex in E. coli includes the proteins TonB, ExbB, and ExbD. Recent structural analysis of this complex reveals the inner membrane spanning ExbB in a pentameric arrangement enclosed around a dimer of ExbD that extends into the periplasm. The structure of the complex with TonB has not been determined but other characterization of TonB suggests at least one copy of TonB interacts with the ExbBD complex via the TonB N-terminal membrane spanning -helix. This N-terminal -helix is followed by a linker region that spans the periplasm and a well-ordered C-terminal domain. The C-terminal domains of characterized TonB proteins share a common fold of three antiparallel -sheets with two -helices (28, 29). The final -strand at the C-terminus directly contacts the TBDT for -sheet pairing with the N-terminal extension of the TBDT plug domain called the TonBox.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Bacteroides Thetaiotaomicron (strain Atcc 29148 / Dsm 2079 / Nctc 10582 / E50 / Vpi-5482)

SUBMITTER: Nicole Koropatkin  

LAB HEAD: Nicole M Koropatkin3

PROVIDER: PXD041518 | Pride | 2024-01-26

REPOSITORIES: Pride