2.A.115 The Novobiocin Exporter (NbcE) Family
The NbcE (formerly the YitT (DUF161)) family consists mostly of 6 TMS proteins, where these TMSs are frequently in a 2 2 2 arrangement. However, distant 5 and 3 TMS proteins may be members of this family. Several homologues are annotated as exporters or efflux transporters. The 3-d structure (PDB# 3HLU_A) is available for YitT of Bacillus subtilis. This protein has a DUF161-DUF161-DUF2179 domain arrangement according to CDD. Most homologues are from bacteria with a preponderance from firmicutes, but others are found in more distantly related organisms. One homologue, NbcE of Lactobacillus brevis, has been shown to be a novobiocin exporter (TC# 2.A.115.2.4). It has 195 aas and 4 or 5 TMSs (Pagliai et al. 2010).