5BY4

Structure and function of the Escherichia coli Tol-Pal stator protein TolR

Summary for 5BY4

• Entry DOI: 10.2210/pdb5by4/pdb
• Descriptor: Protein TolR, SODIUM ION (3 entities in total)
• Functional Keywords: strand-swapped dimer, protein transport
• Biological source: Escherichia coli
• Cellular location: Cell inner membrane; Single-pass type II membrane protein: P0ABV6
• Total number of polymer chains: 1
• Total formula weight: 11774.30

Authors

Wojdyla, J.A.,Kaminska, R.,Kleanthous, C. (deposition date: 2015-06-10, release date: 2015-09-16, Last modification date: 2024-01-10)

Primary citation

Wojdyla, J.A.,Cutts, E.,Kaminska, R.,Papadakos, G.,Hopper, J.T.,Stansfeld, P.J.,Staunton, D.,Robinson, C.V.,Kleanthous, C.
Structure and Function of the Escherichia coli Tol-Pal Stator Protein TolR.
J.Biol.Chem., 290:26675-26687, 2015

PubMed Abstract: TolR is a 15-kDa inner membrane protein subunit of the Tol-Pal complex in Gram-negative bacteria, and its function is poorly understood. Tol-Pal is recruited to cell division sites where it is involved in maintaining the integrity of the outer membrane. TolR is related to MotB, the peptidoglycan (PG)-binding stator protein from the flagellum, suggesting it might serve a similar role in Tol-Pal. The only structure thus far reported for TolR is of the periplasmic domain from Haemophilus influenzae in which N- and C-terminal residues had been deleted (TolR(62-133), Escherichia coli numbering). H. influenzae TolR(62-133) is a symmetrical dimer with a large deep cleft at the dimer interface. Here, we present the 1.7-Å crystal structure of the intact periplasmic domain of E. coli TolR (TolR(36-142)). E. coli TolR(36-142) is also dimeric, but the architecture of the dimer is radically different from that of TolR(62-133) due to the intertwining of its N and C termini. TolR monomers are rotated ∼180° relative to each other as a result of this strand swapping, obliterating the putative PG-binding groove seen in TolR(62-133). We found that removal of the strand-swapped regions (TolR(60-133)) exposes cryptic PG binding activity that is absent in the full-length domain. We conclude that to function as a stator in the Tol-Pal complex dimeric TolR must undergo large scale structural remodeling reminiscent of that proposed for MotB, where the N- and C-terminal sequences unfold in order for the protein to both reach and bind the PG layer ∼90 Å away from the inner membrane.

PubMed: 26354441
DOI: 10.1074/jbc.M115.671586

Experimental method

X-RAY DIFFRACTION (1.702 Å)