Microscopy sheds light on bacterial machines

Researchers have discovered surface and structural properties of organelles in cyanobacteria that enable carbon dioxide's conversion into sugar via photosynthesis.

These polyhedral structures, known as carboxysomes, are comprised of a number of proteins and enzymes. The researchers, for the first time ever, were able to purify these structures before using electron and atomic force microscopy to study them.

Dr Luning Liu, from the University of Liverpool and coauthor of the study, said: “We're now just starting to understand how these bacterial machines are built and work in nature. Our long-term vision is to harness the knowledge to make further steps towards better design and engineering of bio-inspired machines.”

Cyanobacteria are a phylum of bacteria that produce oxygen and energy during photosynthesis, similar to green plants. They are one of the most abundant organisms in oceans and fresh water. The researchers' work has allowed them to examine, in depth, the native structure and mechanical stiffness of carboxysomes.

Although the carboxysomes resemble polyhedral viruses, they are a lot softer and structurally flexible. Little about carboxysomes and how they perform carbon fixing activation was known until this experiment. Dr Liu, said: “It's exciting that we can make the first 'contact' with these nanostructures and understand how they are self-organised and shaped using state-of-the-art techniques available at the University. Our findings provide new clues about the relationship between the structure and functionality of native carboxysomes."

The self-assembly aspect of the virus could be adapted by nanoscientists, synthetic biologists and bioengineers alike, to design new nanomaterials. The study was published in Nanoscale.