Radical SAM enzyme QueE defines a new minimal core fold and metal-dependent mechanism.

Daniel P. Dowling, Nathan A. Bruender, Anthony P. Young, Reid M. McCarty, Vahe Bandarian, Catherine L. Drennan

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


7-carboxy-7-deazaguanine synthase (QueE) catalyzes a key S-adenosyl-L-methionine (AdoMet)- and Mg(2+)-dependent radical-mediated ring contraction step, which is common to the biosynthetic pathways of all deazapurine-containing compounds. QueE is a member of the AdoMet radical superfamily, which employs the 5'-deoxyadenosyl radical from reductive cleavage of AdoMet to initiate chemistry. To provide a mechanistic rationale for this elaborate transformation, we present the crystal structure of a QueE along with structures of pre- and post-turnover states. We find that substrate binds perpendicular to the [4Fe-4S]-bound AdoMet, exposing its C6 hydrogen atom for abstraction and generating the binding site for Mg(2+), which coordinates directly to the substrate. The Burkholderia multivorans structure reported here varies from all other previously characterized members of the AdoMet radical superfamily in that it contains a hypermodified (β6/α3) protein core and an expanded cluster-binding motif, CX14CX2C.

Original languageEnglish (US)
Pages (from-to)106-112
Number of pages7
JournalUnknown Journal
Issue number2
StatePublished - Feb 2014

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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