A site-specific endonuclease from Pseudomonas aeruginosa

Abstract

Pael, a new restriction endonuclease from Pseudomonas aeruginosa clinical strain was isolated and characterized. It recognizes and cleaves the sequence 5′-GCATG↓C-3′ generating DNA fragments with 3′-tetranucleotide sticky ends. DNAs of pBR322, SV40 and bacteriophage λ have one, two and six Pael recognition sites, respectively. Seventytwo strains of Pseudomonas, Clostridium, Escherichia coli, Shigella, Proteus and Saccharomyces were screened for the presence of site-specific endonucleases. Here we describe the Pael restriction enzyme found in Pseudomonas aeruginosa; other data will be published elsewhere. Earlier Hinkle and Miller isolated from P. aeruginosa a PaeR7 restriction endonuclease recognizing and cleaving a sequence 5′-C↓TCGAG-3′ (1). Sequence analysis of DNAs cleaved by PaeI shows that the enzyme is the isoschizomer of SphI (2).