8OQC

Dirhodium tetraacetate/ribonuclease A adduct in the P3221 space group (1 h soaking)

Summary for 8OQC

• Entry DOI: 10.2210/pdb8oqc/pdb
• Descriptor: Ribonuclease pancreatic, tri-(mi2-acetato-(O, O')-diaqua-dirhodium(II, II), FORMIC ACID, ... (6 entities in total)
• Functional Keywords: metal/protein adduct, dirhodium tetraacettate, catalysis, porous material, hydrolase
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 1
• Total formula weight: 14691.26

Authors

Loreto, D.,Merlino, A.,Maity, B.,Ueno, T. (deposition date: 2023-04-12, release date: 2023-06-14, Last modification date: 2024-10-16)

Primary citation

Loreto, D.,Maity, B.,Morita, T.,Nakamura, H.,Merlino, A.,Ueno, T.
Cross-Linked Crystals of Dirhodium Tetraacetate/RNase A Adduct Can Be Used as Heterogeneous Catalysts.
Inorg.Chem., 62:7515-7524, 2023

PubMed Abstract: Due to their unique coordination structure, dirhodium paddlewheel complexes are of interest in several research fields, like medicinal chemistry, catalysis, etc. Previously, these complexes were conjugated to proteins and peptides for developing artificial metalloenzymes as homogeneous catalysts. Fixation of dirhodium complexes into protein crystals is interesting to develop heterogeneous catalysts. Porous solvent channels present in protein crystals can benefit the activity by increasing the probability of substrate collisions at the catalytic Rh binding sites. Toward this goal, the present work describes the use of bovine pancreatic ribonuclease (RNase A) crystals with a pore size of 4 nm (321 space group) for fixing [Rh(OAc)] and developing a heterogeneous catalyst to perform reactions in an aqueous medium. The structure of the [Rh(OAc)]/RNase A adduct was investigated by X-ray crystallography: the metal complex structure remains unperturbed upon protein binding. Using a number of crystal structures, metal complex accumulation over time, within the RNase A crystals, and structures at variable temperatures were evaluated. We also report the large-scale preparation of microcrystals (∼10-20 μm) of the [Rh(OAc)]/RNase A adduct and cross-linking reaction with glutaraldehyde. The catalytic olefin cyclopropanation reaction and self-coupling of diazo compounds by these cross-linked [Rh(OAc)]/RNase A crystals were demonstrated. The results of this work reveal that these systems can be used as heterogeneous catalysts to promote reactions in aqueous solution. Overall, our findings demonstrate that the dirhodium paddlewheel complexes can be fixed in porous biomolecule crystals, like those of RNase A, to prepare biohybrid materials for catalytic applications.

PubMed: 37144589
DOI: 10.1021/acs.inorgchem.3c00852

Experimental method

X-RAY DIFFRACTION (1.5 Å)