title: FtsL, an essential cytoplasmic membrane protein involved in cell division in Escherichia coli.
abstract: We have identified a gene involved in bacterial cell division, located immediately upstream of the ftsI gene in the min 2 region of the Escherichia coli chromosome. This gene, which we named ftsL, was detected through characterization of TnphoA insertions in a plasmid containing this chromosomal region. TnphoA topological analysis and fractionation of alkaline phosphatase fusion proteins indicated that the ftsL gene product is a 13.6-kDa cytoplasmic membrane protein with a cytoplasmic amino terminus, a single membrane-spanning segment, and a periplasmic carboxy terminus. The ftsL gene is essential for cell growth and division. A null mutation in ftsL resulted in inhibition of cell division, formation of long, nonseptate filaments, ultimate cessation of growth, and lysis. Under certain growth conditions, depletion of FtsL or expression of the largest ftsL-phoA fusion produced a variety of cell morphologies, including Y-shaped bacteria, indicating a possible general weakening of the cell wall. The FtsL protein is estimated to be present at about 20 to 40 copies per cell. The periplasmic domain of the protein displays a sequence with features characteristic of leucine zippers, which are involved in protein dimerization.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: L M
authors.initials: LM
authors.lastname: Guzman
authors.forename: J J
authors.initials: JJ
authors.lastname: Barondess
authors.forename: J
authors.initials: J
authors.lastname: Beckwith
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics*; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000737:chemistry / Q000166:cytology / Q000235:genetics*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D010641:Phenotype; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C078387:ftsL protein, E coli