1.B.39 The Bacterial Porin, OmpW (OmpW) Family
OmpW of Salmonella typhimurium has been shown to be required for the efficient efflux of methyl viologen and benzyl viologen (P. Youderian, personal communication). It functions in parallel with OmpD (NmpC in E. coli) which is the major Salmonella porin. OmpW is also the receptor for colicin S4. Homologues are found in many Gram-negative bacterial species including Pseudomonas, Azotobacter, Desulfitobacterium, Burkholderia, Xanthomonas, Rhodobacter, Ralstonia, Delftia and Rickettsia. One homologue is the major outer membrane protein, OprG of Pseudomonas aeruginosa (Gensberg et al., 1999). Another is the outer membrane protein, AlkL, probably involved in alkane transport (van Beilen et al., 1992). An x-ray structure of OmpW has been presented (Albrecht et al. 2006). OmpW exhibits fast internal motion and residual conformational entropy (O'Brien et al. 2020).