4NJI: Crystal Structure Of Quee From Burkholderia Multivorans In Complex With Adomet, 6-carboxy-5,6,7,8-tetrahydropterin, And Mg2+

Citation:
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 (beta6/alpha3) protein core and an expanded cluster-binding motif, CX14CX2C.
PDB ID: 4NJIDownload
MMDB ID: 116294
PDB Deposition Date: 2013/11/10
Updated in MMDB: 2013/12
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 4NJI: dimeric; determined by author and by software (PISA)
Molecular Components in 4NJI
Label Count Molecule
Proteins (2 molecules)
2
7-carboxy-7-deazaguanine Synthase
Molecule annotation
Chemicals (11 molecules)
1
2
2
2
3
2
4
2
5
2
6
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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