title: Cloning and molecular characterization of the HgiCI restriction/modification system from Herpetosiphon giganteus Hpg9 reveals high similarity to BanI.
abstract: The genes coding for the GGYRCC specific restriction/modification system HgiCI from Herpetosiphon giganteus Hpg9 have been cloned in Escherichia coli in three steps. As an initial step, the methyltransferase gene could be obtained after heterologous in vitro selection of a plasmid gene bank by cleavage with the isoschizomeric restriction endonuclease BanI. The adjacent endonuclease gene was cloned following Southern blot analysis of flanking genomic regions. The two genes code for polypeptides of 420 amino acids (M.HgiCI) and 345 amino acids (R.HgiCI). Establishing a functional endonuclease gene could only be achieved using a tightly regulated expression system or by methylation of the genomic DNA prior to transformation of the endonuclease gene. The methyltransferase M.HgiCI shows significant similarities to the family of 5-methylcytidine methyltransferases. Striking similarities could be found with both the isoschizomeric endonuclease and methyltransferase of the BanI restriction/modification system from Bacillus aneurinolyticus.
authors.affiliation: Institut für Mikrobiologie und Molekularbiologie der Justus-Liebig-Universität Giessen, Federal Republic of Germany.
authors.forename: D
authors.initials: D
authors.lastname: Erdmann
authors.forename: A
authors.initials: A
authors.lastname: Düsterhöft
authors.forename: M
authors.initials: M
authors.lastname: Kröger
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D015698:Genomic Library; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology* / Q000235:genetics; D008780:Methyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004269:DNA, Bacterial; D008780:Methyltransferases; D004262:DNA Restriction Enzymes; C051612:endodeoxyribonuclease BanI; D015252:Deoxyribonucleases, Type II Site-Specific