Researchers have identified a previously unknown bacterial protein, the structure of which is being used in the design of protein nanoparticles for the targeted delivery of anticancer drugs to tumours.
A previously unknown protein in a family of bacteria found in soil and the human gut microbiome has been discovered – which could help drug delivery in cancer treatment.
In a paper published in PNAS, researchers at King’s College London and the University of Washington describe the unique 3D structure of this protein, which is now being used to develop cancer drug delivery systems that can target drugs to tumour sites.
The bacterial protein identified by the team, which they have named BeeR, has a similar function to actin – the most abundant protein in the majority of human cells. In the presence of a chemical called ATP, actin molecules can join together into long spiral chains known as filaments. The filaments sit in the outer membrane of cells and have many important functions, including helping cells to maintain their shape, divide and move. Actin can also break down ATP, which triggers the filaments to disassemble.
Bacteria have similar proteins to actin that form filaments in the presence of ATP and help to control cell shape and division. But when studying BeeR, the researchers discovered one striking difference to other actin-like bacterial proteins – its structure.
Dr Julien Bergeron, Senior Lecturer in the Randall Centre for Cell & Molecular Biophysics at King’s, who led the research, said: “We used metagenomics data – extensive sequencing of bacterial genomes from the environment – to identify a previously unknown actin-like protein in a family of bacteria known as Verrucomicrobiota.”
Using the most advanced cryo-electron microscopes, we were able to determine the atomic structure of this protein, demonstrating that instead of a filament, it forms a rigid tube, with a hollow cavity at its centre. This is strikingly different from actin, or any of its other bacterial counterparts.
Dr Julien Bergeron, Senior Lecturer in the Randall Centre for Cell & Molecular Biophysics at King’s
Credit: Kings College London