Nat. Biotechnol. 30, 1232–1239 (2012); published online 8 November 2012; corrected after print 3 May 2013

In the version of this article initially published, on p. 1235, line 32, the wrong MTases were given for the motif GATC. Instead of “...GATC (for M.EcoGI and M.EcoGII)...,” it should have read, “...GATC (for M.EcoGV and M.EcoGVII)....” The error has been corrected for the PDF and HTML versions of this article.