CLONING AND MOLECULAR ANALYSIS OF THE SALMONELLA-ENTERICA ANSP GENE, ENCODING AN L-ASPARAGINE PERMEASE

A gene (ansP), which encodes an L-asparagine permease, has been isolat ed from a cosmid library of Salmonella enterica during screening for r ecombinant clones which encode L-asparaginase. Nucleotide sequence ana lysis reveals that the gene product is a polypeptide of 497 amino acid residues, containing 12 putative transmembrane segments. The calculat ed molecular mass is 54 kDa, although maxicell analysis by SDS-PAGE ga ve an apparent molecular mass of 37 kDa. Comparison of the deduced ami no acid sequence with sequence databases showed significant homology w ith a family of basic and aromatic amino acid permeases. Strains conta ining the cloned ansP gene demonstrated a many-fold increase in L-aspa ragine uptake in comparison with control strains.