The [4Fe-4S] Cluster of HydF Is Essential for [FeFe]-Hydrogenase Maturation
Journal Article
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· Journal of the American Chemical Society
- Montana State Univ., Bozeman, MT (United States)
The organometallic H-cluster of the [FeFe]-hydrogenase is assembled in vivo through a complex process requiring the action of three dedicated maturation enzymes, HydG, HydE, and HydF, as well as the aminomethyl-lipoyl-H-protein (Hmet) of the glycine cleavage system (GCS). Here we probe the role of HydF and its [4Fe-4S] cluster in [FeFe]-hydrogenase maturation by using a defined semisynthetic approach in which [FeI2(μ-SH)2(CO)4(CN)2]2– ([2Fe]E) is used to bypass HydE and HydG, and GCS components are used in place of cell lysate. We show that inclusion of the iron–sulfur carrier protein NfuA and the high-CO-affinity myoglobin variant MbH64L provides dramatically improved hydrogenase activities up to 828 μmol/min/mg, equivalent to the best reported activities for Chlamydomonas reinhardtii [FeFe]-hydrogenase isolated from the native organism. Apo-HydF lacking a [4Fe-4S] cluster provides very little hydrogenase activity; however, full maturation is restored with the addition of NfuA, which we demonstrate reconstitutes the [4Fe-4S] cluster of HydF. In addition, a HydF variant lacking a [4Fe-4S] cluster by changing two cysteine ligands to alanine is completely unable to support either semisynthetic maturation using [2Fe]E, or full maturation using HydG and HydE, even in the presence of NfuA, demonstrating that the HydF [4Fe-4S] cluster is absolutely essential for [FeFe]-hydrogenase maturation. The possibility that the HydF [4Fe-4S] cluster plays a role in direct binding of [2Fe]E is negated by our results with the HydFD311C variant, which demonstrate that the labile Asp311 cluster ligand is not essential for [2Fe]E binding and HydA maturation. We therefore conclude that [2Fe]E binds HydF adjacent to, but not directly coordinated to, the [4Fe-4S] cluster. The HydF [4Fe-4S] cluster is proposed to be essential due to its impact on the [2Fe]E binding orientation and the ability of the HydF/[2Fe]E complex to form productive interactions with Hmet or the Hmet/T-protein complex during DTMA ligand biosynthesis.
- Research Organization:
- Montana State Univ., Bozeman, MT (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0005404
- OSTI ID:
- 3010489
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 51 Vol. 147; ISSN 0002-7863; ISSN 1520-5126
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Semisynthetic maturation of [FeFe]-hydrogenase using [Fe2 (μ-SH)2 (CN)2 (CO)4 ]2-: key roles for HydF and GTP
Journal Article
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Sat Dec 31 19:00:00 EST 2022
· ChemComm
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OSTI ID:2419700