BspRI restriction endonuclease: Cloning, expression in Escherichia coli and sequential cleavage mechanism

Támas Rasko, András Dér, Éva Klement, Krystyna Ślaska-Kiss, Eszter Pósfai, Katalin F. Medzihradszky, Daniel R. Marshak, Richard J. Roberts, Antal Kiss

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The GGCC-specific restriction endonuclease BspRI is one of the few Type IIP restriction endonucleases, which were suggested to be a monomer. Amino acid sequence information obtained by Edman sequencing and mass spectrometry analysis was used to clone the gene encoding BspRI. The bspRIR gene is located adjacently to the gene of the cognate modification methyltransferase and encodes a 304 aa protein. Expression of the bspRIR gene in Escherichia coli was dependent on the replacement of the native TTG initiation codon with an ATG codon, explaining previous failures in cloning the gene using functional selection. A plasmid containing a single BspRI recognition site was used to analyze kinetically nicking and secondstrand cleavage under steady-state conditions. Cleavage of the supercoiled plasmid went through a relaxed intermediate indicating sequential hydrolysis of the two strands. Results of the kinetic analysis of the first- and second-strand cleavage are consistent with cutting the double-stranded substrate site in two independent binding events. A database search identified eight putative restriction-modification systems in which the predicted endonucleases as well as the methyltransferases share high sequence similarity with the corresponding protein of the BspRI system. BspRI and the related putative restriction endonucleases belong to the PD-(D/E)XK nuclease superfamily.

Original languageEnglish (US)
Pages (from-to)7155-7166
Number of pages12
JournalNucleic acids research
Issue number20
StatePublished - Nov 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics


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