[FeFe]-hydrogenase maturation: H-cluster assembly intermediates tracked by electron paramagnetic resonance, infrared, and X-ray absorption spectroscopy

Németh, BrigittaUppsala universitet,Molekylär biomimetik,Montana State Univ, Dept Chem & Biochem, Bozeman, MT 59717 USA. (författare)

[FeFe]-hydrogenase maturation : H-cluster assembly intermediates tracked by electron paramagnetic resonance, infrared, and X-ray absorption spectroscopy

[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt =NH(CH2S)(2)).[FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe](adt)). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe](adt). The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred'-CO-like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster. [GRAPHICS] .

Senger, MoritzUppsala universitet,Fysikalisk kemi,Free Univ Berlin, Phys Dept, Mol Biophys, D-14195 Berlin, Germany.(Swepub:uu)morse459 (författare)
Redman, Holly J.Uppsala universitet,Molekylär biomimetik(Swepub:uu)holre224 (författare)
Ceccaldi, PierreUppsala universitet,Molekylär biomimetik (författare)
Broderick, JoanMontana State Univ, Dept Chem & Biochem, Bozeman, MT 59717 USA. (författare)
Magnuson, AnnUppsala universitet,Molekylär biomimetik(Swepub:uu)anmag178 (författare)
Stripp, Sven T.Free Univ Berlin, Phys Dept, Mol Biophys, D-14195 Berlin, Germany. (författare)
Haumann, MichaelFree Univ Berlin, Phys Dept, Biophys Metalloenzymes, D-14195 Berlin, Germany. (författare)
Berggren, GustavUppsala universitet,Molekylär biomimetik(Swepub:uu)guber255 (författare)
Uppsala universitetMolekylär biomimetik (creator_code:org_t)

Ingår i:Journal of Biological Inorganic Chemistry: Springer Nature25:5, s. 777-7880949-82571432-1327

Av författaren/redakt...: Németh, Brigitta; Senger, Moritz; Redman, Holly J.; Ceccaldi, Pierre; Broderick, Joan; Magnuson, Ann; visa fler...; Stripp, Sven T.; Haumann, Michael; Berggren, Gustav; visa färre...

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