Formation 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: 10.1107/S2052252519006651
- Primary Citation of Related Structures:
- 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 fasc ...
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.
Department of Chemistry, University of the Free State, Nelson Mandela Drive, Bloemfontein, 9301, South Africa.,School of Chemistry, University of Manchester, Brunswick Street, Manchester M13 9PL, UK.