<p>RhtX from <taxon tax_id="266834">Sinorhizobium meliloti 1021</taxon> and FptX from <taxon tax_id="287">Pseudomonas aeruginosa</taxon> appear to be single polypeptide transporters, from the major facilitator family for import of siderophores as a means to import iron. This function was suggested by proximity to siderophore biosynthesis genes and then confirmed by study of knockout and heterologous expression phenotypes.</p> Siderophore transporter, RhtX/FptX family