Skip to main content
. 2014 Jun 26;10(6):e1004209. doi: 10.1371/journal.ppat.1004209

Figure 12. A proposed model of Fra protein localization and functions.

Figure 12

A proteomic survey of subcellular fractions of Salmonella previously identified FraB (the deglycase) as cytoplasmic and FraE (the asparaginase) as periplasmic [79]. Therefore, it is possible that F-Asn is converted to F-Asp in the periplasm by the asparaginase and that the transporter and kinase actually use F-Asp as substrate rather than F-Asn. The FraD kinase of Salmonella shares 30% amino acid identity with the FrlD kinase of E. coli. FrlD phosphorylates F-Lys to form F-Lys-6-P [28]. Therefore, we hypothesize that FraD phosphorylates F-Asp to form F-Asp-6-P. The FrlB deglycase of E. coli shares 28% amino acid identity with FraB of Salmonella. The FrlB deglycase converts F-Lys-6-P to lysine and glucose-6-P [28], so we hypothesize that FraB of Salmonella converts F-Asp-6-P to aspartate and glucose-6-P.