4WCX

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

4WCX の概要

• エントリーDOI: 10.2210/pdb4wcx/pdb
• 分子名称: Biotin and thiamin synthesis associated, IRON/SULFUR CLUSTER, METHIONINE, ... (9 entities in total)
• 機能のキーワード: [fefe]-hydrogenase, maturase, lyase
• 由来する生物種: Thermoanaerobacter italicus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 112682.60

構造登録者

Dinis, P.C.,Harmer, J.E.,Driesener, R.C.,Roach, P.L. (登録日: 2014-09-05, 公開日: 2015-02-04, 最終更新日: 2024-05-08)

主引用文献

Dinis, P.,Suess, D.L.,Fox, S.J.,Harmer, J.E.,Driesener, R.C.,De La Paz, L.,Swartz, J.R.,Essex, J.W.,Britt, R.D.,Roach, P.L.
X-ray crystallographic and EPR spectroscopic analysis of HydG, a maturase in [FeFe]-hydrogenase H-cluster assembly.
Proc.Natl.Acad.Sci.USA, 112:1362-1367, 2015

PubMed Abstract: 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 (βα)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 μ2-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.

PubMed: 25605932
DOI: 10.1073/pnas.1417252112

実験手法

X-RAY DIFFRACTION (1.59 Å)