9JN8

Crystal structure of a thioredoxin-like ferredoxin of Rhodobacter capsulatus

Summary for 9JN8

• Entry DOI: 10.2210/pdb9jn8/pdb
• Descriptor: ORF378, FE2/S2 (INORGANIC) CLUSTER (3 entities in total)
• Functional Keywords: ferredoxin, [2fe-2s] cluster, thioredoxin fold, electron transport
• Biological source: Rhodobacter capsulatus
• Total number of polymer chains: 3
• Total formula weight: 43440.51

Authors

Shen, Y.,Liu, L. (deposition date: 2024-09-22, release date: 2025-02-19, Last modification date: 2025-04-02)

Primary citation

Shen, Y.H.,Cheng, W.L.,Wang, X.,Dai, H.E.,Wang, M.,Liu, L.
Crystal Structure of a Thioredoxin-like Ferredoxin Encoded Within a Cobalamin Biosynthetic Operon of Rhodobacter capsulatus.
Protein J., 44:192-200, 2025

PubMed Abstract: Thioredoxin-like ferredoxin is a small homodimeric protein containing a [2Fe-2S] cluster in each monomer. It is only found in bacteria but its physiological function remains largely unknown. The cobalamin biosynthetic operon in the genome of the purple phototroph Rhodobacter capsulatus encodes a putative ferredoxin dubbed as CfrX. To characterize this protein, we cloned, expressed, purified, and crystalized the recombinant CfrX in the iron-sulfur cluster-bound state, and solved the structure at 2.1-Å resolution. Adopting a typical thioredoxin-like ferredoxin fold, a CfrX monomer binds one [2Fe-2S] cluster through four Cys residues located on two protruding loops. Unexpectedly, CfrX dimerizes in a previously unreported manner. With the structural information, we ascertained CfrX as a thioredoxin-like ferredoxin. While the precise function of CfrX in cobalamin biosynthesis is elusive, a link between CfrX and aerobic cobaltochelatase should exist due to the gene clustering pattern. We also discussed the possible relationship among CfrX, CobW, and CobNST with respect to the [2Fe-2S] cluster.

PubMed: 39924633
DOI: 10.1007/s10930-025-10254-z

Experimental method

X-RAY DIFFRACTION (2.12 Å)