A Cryptic Melibiose Transporter Gene Possessing a Frameshift from Citrobacter freundii.

概要

論文の詳細を見る
Wild-type Citrobacter freundii cannot grow on melibiose as a sole source of carbon. The melibiose transporter gene melB was cloned froma C. freundii mutant M4 that could utilize melibiose as a sole carbon source- Although the cloned melB gene is closely siunilar to the melB genes of other bacteria, it is cryptic because of a frameshift mutation. Site-directed mutagenesis was used to construct a functional melB gene by deleting one nucleotide, resulting in the production of an active melibiose transporter. The active MelB transporter could utilize Na+ and H+ as coupling cation to melibiose transport. The amino acid sequence of the C. freundii MelB was found to be most similar to those of Salmonella typhimurium and Escherichia coli MelB. These facts are consistent with the phylogenetic relationship of bacteria and the cation coupling properties of the melibiose transporters.
社団法人日本生化学会の論文