9.B.186 The Putative Lipoprotein Suppressor of a ts bamD mutant, YiaD (YiaD) Family

Tachikawa and Kato 2011 isolated temperature-sensitive mutants of the E. coli bamD gene, which is essential for the assembly of β-barrel outer membrane proteins. As their multicopy suppressor, they identified a novel yiaD gene encoding a putative lipoprotein, YiaD with 3 putative N-terminal TMSs and a C-terminal peptidoglycan-binding domain. Mutations of its OmpA domain, which is required for interaction with peptidoglycan, affected suppression, suggesting that interaction with peptidoglycan is important for YiaD function.

These proteins show extensive sequence similarity with members of TC families 1.B.6 and 9.B.153, at least in part, and are homologous to them in these regions.  Since family 1.B.6 members are members of the TC Outer Membrane Pore-forming Protein (OMPPI) Superfamily I, families 9.B.186, 9.B.153 and 9.B.170, are probably also member of this superfamily. However, if this is just an OmpA-like peptidoglycan binding-domain, these families may not be bonefide members of this superfamily.