29KI

Spinach Ferredoxin I, Reduced, -400 mV

Summary for 29KI

• Entry DOI: 10.2210/pdb29ki/pdb
• Related: 9TXE 9TXO 9TXQ
• Descriptor: Ferredoxin-1, chloroplastic, FE2/S2 (INORGANIC) CLUSTER (3 entities in total)
• Functional Keywords: redox, metalloprotein, iron-sulfur cluster, electron transport
• Biological source: Spinacia oleracea (spinach)
• Total number of polymer chains: 1
• Total formula weight: 11449.08

Authors

Laxmi, S.,Carr, S.B.,Vincent, K.A. (deposition date: 2026-03-17, release date: 2026-05-13)

Primary citation

Laxmi, S.,Jaho, S.,Myers, W.K.,Vincent, K.A.,Carr, S.B.
Crystallise, poise, capture: a multimodal platform for correlated structural and spectroscopic characterisation of redox enzymes.
J.Biol.Inorg.Chem., 2026

PubMed Abstract: Iron-sulfur (Fe-S) clusters are ubiquitous as redox-active protein cofactors, but it is often difficult to collect protein structures in which redox centres are in uniform and well-defined oxidation states. Using spinach ferredoxin I (Fdx) as a model redox protein, we demonstrate an integrated methodological pathway for electrochemical modulation of redox state in protein crystals coupled with in crystallo EPR and online-UV-visible spectroscopy to verify oxidation state. We show that Fdx crystals can be electrochemically reduced, reversibly, without compromising lattice integrity or X-ray diffraction quality. We show that redox levels can be precisely ascertained in crystallo via EPR and UV-visible spectroscopy, enabling a direct correlation between protein structure and electronic state of the metal cluster. In this way, we generate and compare 'oxidised', 'reduced' and 're-oxidised' structures of Fdx. Overall, our approach demonstrates a pipeline which will be applicable to structure-function studies of a wide range of electron-transfer proteins and redox enzymes.

PubMed: 42082801
DOI: 10.1007/s00775-026-02148-x

Experimental method

X-RAY DIFFRACTION (1.11 Å)