9T05

X-ray structure of the adduct formed by dirhodium tetraacetate with a C-phycocyanin

This is a non-PDB format compatible entry.

Summary for 9T05

• Entry DOI: 10.2210/pdb9t05/pdb
• Descriptor: C-phycocyanin alpha subunit, C-phycocyanin beta chain, PHYCOCYANOBILIN, ... (6 entities in total)
• Functional Keywords: dirhodium compounds; paddlewheel dimetallic complexes; metal-protein adducts; metallodrugs; protein metalation, photosynthesis
• Biological source: Galdieria phlegrea; More
• Total number of polymer chains: 12
• Total formula weight: 229546.10

Authors

Merlino, A.,Ferraro, G. (deposition date: 2025-10-16, release date: 2025-12-17, Last modification date: 2025-12-24)

Primary citation

Ferraro, G.,Imbimbo, P.,Troisi, R.,Monti, D.M.,Merlino, A.
Coordination of a Dirhodium(II) Center to Methionine and Cysteine Side Chains: Evidence from X-Ray Structure of the Adduct Formed by Dirhodium Tetraacetate with a C-Phycocyanin.
Int J Mol Sci, 26:-, 2025

PubMed Abstract: Upon reaction of dirhodium tetraacetate ([Rh(μ-OCCH)]) and some [Rh(μ-OCCH)] derivatives with proteins, dimeric Rh-Rh units (diRh) or monometallic moieties can bind the side chains of His, Cys, Met, Asp, Asn, Arg and Lys, and the C-terminal carboxylate. However, structural data on the interaction between the diRh center and Cys and Met side chains within the protein environment are still missing. Here, we report the X-ray structure of the adduct that [Rh(μ-OCCH)] forms with C-phycocyanin from at 2.17 Å resolution. Twelve diRh binding sites were found on the protein structure, two for each (αβ) unit. Dimetallic fragments were observed close to the side chains of Met30 of β-chains and of Cys73 of α-chains. To the best of our knowledge, the results provide the first unambiguous crystallographic observation of the diRh center binding to Met and Cys protein residues. DiRh binding does not alter overall protein structure and stability. This result will help in the design of new dirhodium-based artificial metalloenzymes.

PubMed: 41373647
DOI: 10.3390/ijms262311492

Experimental method

X-RAY DIFFRACTION (2.169 Å)