InterPro: IPR011042 Six-bladed beta-propeller, TolB-like

This entry represents a six-bladed beta-propeller domain consisting of six 4-stranded beta-sheet motifs. This domain can be found in TolB proteins (C-terminal), in soluble quinoprotein glucose dehydrogenase, in calcium-dependent phosphotriesterases, in the low density lipoprotein (LDL) receptor YWTD domain, in nidogen, and in serine/threonine-protein kinase (PknD) NHL repeat domain.

TolB is a periplasmic protein from Escherichia coli that is part of the Tol-dependent translocation system involving group A and E colicins that is used to penetrate and kill cells [1, 2]. TolB has two domains, an alpha-helical N-terminal domain (IPR007195) that shares structural similarity with the C-terminal domain of transfer RNA ligases, and a beta-propeller C-terminal domain that shares structural similarity with numerous members of the prolyl oligopeptidase family and, to a lesser extent, to class B metallo-beta-lactamases (although its does not necessarily occur at the C-terminal in these proteins) [1]. The C-terminal domain of TolB may mediate protein-protein interactions with colicins.