4wcx | pdb_00004wcx

Crystal structure of HydG: A maturase of the [FeFe]-hydrogenase

spinqualitylabelsall models 4wcx, resolution 1.59Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4wcx is a 2 chain structure with sequence from Thermoanaerobacter italicus Ab9. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ALA, FE, H2S, MET, NA, SAM, SF4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function D3T7F1_THEIA Publication Abstract from PubMed Hydrogenases use complex metal cofactors to catalyze the reversible formation of hydrogen. In [FeFe]-hydrogenases, the H-cluster cofactor includes a diiron subcluster containing azadithiolate, three CO, and two CN(-) ligands. During the assembly of the H cluster, the radical S-adenosyl methionine (SAM) enzyme HydG lyses the substrate tyrosine to yield the diatomic ligands. These diatomic products form an enzyme-bound Fe(CO)x(CN)y synthon that serves as a precursor for eventual H-cluster assembly. To further elucidate the mechanism of this complex reaction, we report the crystal structure and EPR analysis of HydG. At one end of the HydG (betaalpha)8 triosephosphate isomerase (TIM) barrel, a canonical [4Fe-4S] cluster binds SAM in close proximity to the proposed tyrosine binding site. At the opposite end of the active-site cavity, the structure reveals the auxiliary Fe-S cluster in two states: one monomer contains a [4Fe-5S] cluster, and the other monomer contains a [5Fe-5S] cluster consisting of a [4Fe-4S] cubane bridged by a mu2-sulfide ion to a mononuclear Fe(2+) center. This fifth iron is held in place by a single highly conserved protein-derived ligand: histidine 265. EPR analysis confirms the presence of the [5Fe-5S] cluster, which on incubation with cyanide, undergoes loss of the labile iron to yield a [4Fe-4S] cluster. We hypothesize that the labile iron of the [5Fe-5S] cluster is the site of Fe(CO)x(CN)y synthon formation and that the limited bonding between this iron and HydG may facilitate transfer of the intact synthon to its cognate acceptor for subsequent H-cluster assembly. X-ray crystallographic and EPR spectroscopic analysis of HydG, a maturase in [FeFe]-hydrogenase H-cluster assembly.,Dinis P, Suess DL, Fox SJ, Harmer JE, Driesener RC, De La Paz L, Swartz JR, Essex JW, Britt RD, Roach PL Proc Natl Acad Sci U S A. 2015 Feb 3;112(5):1362-7. doi: 10.1073/pnas.1417252112., Epub 2015 Jan 20. PMID:25605932 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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