4RTB:
reference: Crystal Structure of HydG from Carboxydothermus hydrogenoformans: A Trifunctional [FeFe]-Hydrogenase Maturase., Nicolet Y, Pagnier A, Zeppieri L, Martin L, Amara P, Fontecilla-Camps JC, Chembiochem. 2014 Dec 10. doi: 10.1002/cbic.201402661. PMID: 25504963

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