title: Cloning and molecular analysis of a mannitol operon of phosphoenolpyruvate-dependent phosphotransferase (PTS) type from Vibrio cholerae O395.
abstract: A putative mannitol operon of the phosphoenolpyruvate phosphotransferase (PTS) type was cloned from Vibrio cholerae O395, and its activity was studied in Escherichia coli. The 3.9-kb operon comprising three genes is organized as mtlADR. Based on the sequence analysis, these were identified as genes encoding a putative mannitol-specific enzyme IICBA (EII(Mtl)) component (MtlA), a mannitol-1-phosphate dehydrogenase (MtlD), and a mannitol operon repressor (MtlR). The transport of [(3)H]mannitol by the cloned mannitol operon in E. coli was 13.8 ± 1.4 nmol/min/mg protein. The insertional inactivation of EII(Mtl) abolished mannitol and sorbitol transport in V. cholerae O395. Comparison of the mannitol utilization apparatus of V. cholerae with those of Gram-negative and Gram-positive bacteria suggests highly conserved nature of the system. MtlA and MtlD exhibit 75% similarity with corresponding sequences of E. coli mannitol operon genes, while MtlR has 63% similarity with MtlR of E. coli. The cloning of V. cholerae mannitol utilization system in an E. coli background will help in elucidating the functional properties of this operon.
authors.affiliation: Department of Biology, Eastern New Mexico University, Portales, NM 88130, USA.
authors.forename: Sanath
authors.initials: S
authors.lastname: Kumar
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Smith
authors.forename: Jody L
authors.initials: JL
authors.lastname: Floyd
authors.forename: Manuel F
authors.initials: MF
authors.lastname: Varela
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005285:Fermentation; D008353:Mannitol / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D014734:Vibrio cholerae / Q000201:enzymology / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D008353:Mannitol; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System