Nat. Chem. Biol. 13, 858–866 (2017); published online 5 June 2017; corrected after print 10 July 2017

In the version of this article initially published, a sentence in the abstract, “Members of these families are prone to incorrect annotation because MetA and MetX enzymes are assumed to always use acetyl-CoA and succinyl-CoA, respectively,” had the order of enzymes MetA and MetX reversed. The sentence should read, “Members of these families are prone to incorrect annotation because MetX and MetA enzymes are assumed to always use acetyl-CoA and succinyl-CoA, respectively.” The error has been corrected in the HTML and PDF versions of the article.