6c8v

X-ray structure of PqqE from Methylobacterium extorquens

spinqualitylabelsall models 6c8v, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6c8v is a 1 chain structure with sequence from "bacillus_extorquens"_bassalik_1913 "bacillus extorquens" bassalik 1913. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FES, SF4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The Radical SAM (RS) enzyme PqqE catalyzes the first step in the biosynthesis of the bacterial cofactor pyrroloquinoline quinone, forming a new carbon-carbon bond between two side chains within the ribosomally synthesized peptide substrate PqqA. In addition to the active site RS 4Fe-4S cluster, PqqE is predicted to have two auxiliary Fe-S clusters, like the other members of the SPASM domain family. Here we identify these sites and examine their structure using a combination of X-ray crystallography and Mossbauer and electron paramagnetic resonance (EPR) spectroscopies. X-ray crystallography allows us to identify the ligands to each of the two auxiliary clusters at the C-terminal region of the protein. The auxiliary cluster nearest the RS site (AuxI) is in the form of a 2Fe-2S cluster ligated by four cysteines, an Fe-S center not seen previously in other SPASM domain proteins; this assignment is further supported by Mossbauer and EPR spectroscopies. The second, more remote cluster (AuxII) is a 4Fe-4S center that is ligated by three cysteine residues and one aspartate residue. In addition, we examined the roles these ligands play in catalysis by the RS and AuxII clusters using site-directed mutagenesis coupled with EPR spectroscopy. Lastly, we discuss the possible functional consequences that these unique AuxI and AuxII clusters may have in catalysis for PqqE and how these may extend to additional RS enzymes catalyzing the post-translational modification of ribosomally encoded peptides. X-ray and EPR Characterization of the Auxiliary Fe-S Clusters in the Radical SAM Enzyme PqqE.,Barr I, Stich TA, Gizzi AS, Grove TL, Bonanno JB, Latham JA, Chung T, Wilmot CM, Britt RD, Almo SC, Klinman JP Biochemistry. 2018 Feb 6. doi: 10.1021/acs.biochem.7b01097. PMID:29405700 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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