Description
Experimental Technique/Method:X-RAY DIFFRACTION
Resolution:2.2
Classification:LYASE
Release Date:2013-12-25
Deposition Date:2013-11-10
Revision Date:2014-01-22#2014-02-05#2014-07-02
Molecular Weight:52871.5
Macromolecule Type:Protein
Residue Count:460
Atom Site Count:3374
DOI:10.2210/pdb4nji/pdb
Abstract:
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.
Resolution:2.2
Classification:LYASE
Release Date:2013-12-25
Deposition Date:2013-11-10
Revision Date:2014-01-22#2014-02-05#2014-07-02
Molecular Weight:52871.5
Macromolecule Type:Protein
Residue Count:460
Atom Site Count:3374
DOI:10.2210/pdb4nji/pdb
Abstract:
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.
| Date made available | 2013 |
|---|---|
| Publisher | RCSB-PDB |