title: Cloning and analysis of translational control for genes encoding the Cfr9I restriction-modification system.
abstract: The complete type-II Cfr9I restriction-modification (R-M) system of Citrobacter freundii strain RFL9, recognizing the DNA sequence CCCGGG, has been cloned and expressed, and functionally active enzymes have been produced in Escherichia coli. Both the methyltransferase (MTase; M.Cfr9I) and restriction endonuclease (ENase; R.Cfr9I) were found to be encoded on a 2.3-kb cloned fragment in the same transcriptional orientation, but differing in translational phases. The last codon (underlined) (ATGA) of the MTase-encoding gene (Cfr9IM) overlaps with the start codon for the ENase-encoding gene (overlined) (cfr9IR). A nucleotide sequence complementary to a predicted Shine-Dalgarno sequence preceding cfr9IR is within this gene. Predicted free energy (delta G) for formation of the mRNA secondary structure involving these complementary sequences was found to be -16.1 kcal/mol. Amino-acid sequence homology of 80% was found between R.Cfr9I and R.XcyI.
authors.affiliation: Institute of Biotechnology FERMENTAS, Vilnius, Lithuania.
authors.forename: A
authors.initials: A
authors.lastname: Lubys
authors.forename: S
authors.initials: S
authors.lastname: Menkevicius
authors.forename: A
authors.initials: A
authors.lastname: Timinskas
authors.forename: V
authors.initials: V
authors.lastname: Butkus
authors.forename: A
authors.initials: A
authors.lastname: Janulaitis
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D016971:Citrobacter freundii / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D015254:DNA Modification Methylases / Q000235:genetics*; D004269:DNA, Bacterial / Q000302:isolation & purification; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides; D014176:Protein Biosynthesis / Q000235:genetics*; D016364:Reading Frames; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D004269:DNA, Bacterial; D009838:Oligodeoxyribonucleotides; D015254:DNA Modification Methylases; D015252:Deoxyribonucleases, Type II Site-Specific