Nucleotide sequence of the PaeR7 restriction/modification system and partial characterization of its protein products

• Published in: Nucleic acids research 1985-12, Vol.13 (23), p.8441-8461
• Main Authors: Theriault, G., Roy, P.H., Howard, K.A., Benner, J.S., Brooks, J.E., Waters, A.F., Gingeras, T.R.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Base Sequence; Biological and medical sciences; Cell-Free System; Cloning, Molecular; Deoxyribonucleases, Type II Site-Specific; DNA Restriction Enzymes - genetics; DNA Restriction Enzymes - isolation & purification; DNA-Cytosine Methylases; Escherichia coli; Fundamental and applied biological sciences. Psychology; gene products; Genes; Genes, Bacterial; Genes. Genome; Methyltransferases - genetics; Methyltransferases - isolation & purification; Molecular and cellular biology; Molecular genetics; nucleotide sequence; operons; Plasmids; Protein Biosynthesis; Pseudomonas aeruginosa; Pseudomonas aeruginosa - genetics; restriction-modification; Transcription, Genetic
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/13.23.8441

Bal31 delation experiments on clones of the PaeR7 restriction-modification system from Pseudomonas aeruginosa demonstrate that it is arranged as an operon, with the methylase gene preceding the endonuclease gene. The DNA sequence of this operon agrees with in vitro transcription-translation assays which predict proteins of 532 amino acids, Mr = 59,260 daltons, and 246 amino acids, Mr = 27,280 daltons, coincident with the methylase and endonuclease genes, respectively. These predicted values coincide with the measured molecular weights of the purified, denatured PaeR7 endonuclease and methylase proteins. The first twenty amino acids from the amino-terminus of the purified endonuclease exactly match those predicted from the DNA sequence. Finally, potential regulatory mechanisms for the expression of phage restriction are described based on the properties of several PaeR7 subclones.