CLONING AND SEQUENCING OF THE GENE FOR THE LACTOSE CARRIER OF CITROBACTER-FREUNDII

The gene coding for the lactose carrier of Citrobacter freundii was cl oned into the plasmid pBR322. The gene was sequenced and the amino aci d sequence was found to be 70% identical to the lactose carrier of E. coli. All of the charged residues in the membrane spanning region were conserved. The sugar specificity is somewhat different from that of E . coli. The C. freundii carrier has less activity for lactose and more activity for o-nitrophenylgalactose (ONPG) than the carrier of E. col i. (C) 1994 Academic Press. Inc.