Work

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

Year: 2025

Type: article

Abstract: Upon reaction of dirhodium tetraacetate ([Rh2(μ-O2CCH3)4]) and some [Rh2(μ-O2CCH3)4] 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 [Rh2(μ-O2CCH3)4] forms with C-phycocyanin from Galdiera phlegrea 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.

Source: International Journal of Molecular Sciences

DOI: 10.3390/ijms262311492

Authors: Giarita Ferraro, Paola Imbimbo, Romualdo Troisi, Daria Maria Monti, Antonello Merlino

Institution: University of Naples Federico II

Language: English

Topic: Metal-Catalyzed Oxygenation Mechanisms

Subfield: Inorganic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,499

Funder: Ministero dell'Università e della Ricerca