9GYR

Ferredoxin CNF labelled, oxidised state

Summary for 9GYR

• Entry DOI: 10.2210/pdb9gyr/pdb
• Descriptor: Ferredoxin-1, chloroplastic, FE2/S2 (INORGANIC) CLUSTER (3 entities in total)
• Functional Keywords: metalloprotein iron-sulfur cluster electron transfer, oxidoreductase
• Biological source: Spinacia oleracea (spinach)
• Total number of polymer chains: 4
• Total formula weight: 45832.35

Authors

Carr, S.B.,Wei, J.,Vincent, K.A. (deposition date: 2024-10-02, release date: 2025-05-28, Last modification date: 2025-07-30)

Primary citation

Duan, Z.,Wei, J.,Carr, S.B.,Ramirez, M.,Evans, R.M.,Ash, P.A.,Rodriguez-Macia, P.,Sachdeva, A.,Vincent, K.A.
Cyanophenylalanine as an Infrared Probe for Iron-Sulfur Cluster Redox State in Multicenter Metalloenzymes.
Chembiochem, 26:e202500251-e202500251, 2025

PubMed Abstract: The noncanonical amino acid, para-cyanophenylalanine (CNF), when incorporated into metalloproteins, functions as an infrared spectroscopic probe for the redox state of iron-sulfur clusters, offering a strategy for determining electron occupancy in the electron transport chains of complex metalloenzymes. A redshift of ≈1-2 cm in the nitrile (NC) stretching frequency is observed, following reduction of spinach ferredoxin modified to contain CNF close to its [2Fe-2S] center, and this shift is reversed on re-oxidation. We extend this to CNF positioned near to the proximal [4Fe-4S] cluster of the [FeFe] hydrogenase from Desulfovibrio desulfuricans. In combination with a distal [4Fe-4S] cluster and the [4Fe-4S] cluster of the active site 'H-cluster' ([4Fe-4S]), the proximal cluster forms an electron relay connecting the active site to the surface of the protein. Again, a reversible shift in wavenumber for CNF is observed, following cluster reduction in either apo-protein (containing the iron-sulfur clusters but lacking the active site) or holo-protein with intact active site, demonstrating the general applicability of this approach to studying complex metalloenzymes.

PubMed: 40347495
DOI: 10.1002/cbic.202500251

Experimental method

X-RAY DIFFRACTION (1.1 Å)