Download MendeleyFormation of a highly dense tetra-rhenium cluster in a protein crystal and its implications in medical imaging.
Brink, A., Helliwell, J.R.(2019) IUCrJ 6: 695-702
- PubMed: 31316813
- DOI: https://doi.org/10.1107/S2052252519006651
- Primary Citation of Related Structures:
6RO3, 6RO5 - PubMed Abstract:
The fact that a protein crystal can serve as a chemical reaction vessel is intrinsically fascinating. That it can produce an electron-dense tetranuclear rhenium cluster compound from a rhenium tri-carbonyl tri-bromo starting compound adds to the fascination. Such a cluster has been synthesized previously in vitro , where it formed under basic conditions. Therefore, its synthesis in a protein crystal grown at pH 4.5 is even more unexpected. The X-ray crystal structures presented here are for the protein hen egg-white lysozyme incubated with a rhenium tri-carbonyl tri-bromo compound for periods of one and two years. These reveal a completed, very well resolved, tetra-rhenium cluster after two years and an intermediate state, where the carbonyl ligands to the rhenium cluster are not yet clearly resolved, after one year. A dense tetranuclear rhenium cluster, and its technetium form, offer enhanced contrast in medical imaging. Stimulated by these crystallography results, the unusual formation of such a species directly in an in vivo situation has been considered. It offers a new option for medical imaging compounds, particularly when considering the application of the pre-formed tetranuclear cluster, suggesting that it may be suitable for medical diagnosis because of its stability, preference of formation and biological compatibility.
Organizational Affiliation:
Department of Chemistry, University of the Free State, Nelson Mandela Drive, Bloemfontein, 9301, South Africa.
