UQ researchers have developed a novel cell-free protein production system that will allow more effective research into the molecular basis of disease and the development of new therapies.
Proteins are involved in almost all biological processes, so the ability to manufacture large numbers of proteins to specification is very important for scientific research and medicine.
Proteins are produced when DNA is translated into an RNA blueprint, which contains instructions for assembling the protein. The translation process is initiated by a specific RNA sequence.
Led by Professor Kirill Alexandrov from the Institute for Molecular Bioscience, the researchers from UQ and the Max Planck Institute for Molecular Physiology in Germany engineered a protein production system that uses a universal initiation sequence.
“Most translation-initiating sequences are species-specific, so anytime you wanted to create a transgenic organism, you needed to identify an optimal translation-initiating sequence,” said Professor Alexandrov, who holds a joint appointment with the Australian Institute for Bioengineering and Nanotechnology.
“We have created a universal initiation sequence, so proteins can be produced in any organism. It’s a tool that allows us to put proteins rapidly through different systems to see which is better at making the protein.”
The sequence is been used as a part of a cell-free system, which involves producing proteins without using living cells. Cell-free systems manufacture proteins more rapidly, but until now the only production-scale relevant systems were confined to prokaryotic organisms, especially E. coli.
Prokaryotes are simple organisms without a cell nucleus, such as bacteria. The other type of organism is eukaryotes, which have a cell nucleus and are more complex organisms.
Prokaryotic cell production systems can produce large amounts of recombinant proteins, but they can’t fold them. Eukaryotic systems are more expensive and less efficient, but they can fold proteins, making them biologically active. Professor Alexandrov and his team found a compromise by exploiting Leishmania tarentolae, a lizard parasite that doesn’t affect humans.
“Leishmania tarentolae is between the prokaryotic and eukaryotic worlds,” Professor Alexandrov said. “It has a prokaryotic way of synthesising RNA which makes the system much easier to manipulate and a eukaryotic way of folding proteins, making them more suitable for production of human proteins.”
The new system will also be useful in analysing protein interactions by using synthetic biology approaches. This is a way of testing how living systems work by building an artificial version.
“We could use this system to convert large gene clusters into active proteins, thus reconstructing key structural and regulation blocks of a cell. This will allow us to study how proteins work in an environment completely controlled by us,” Professor Alexandrov said.
“There are all kinds of applications for this work, from structural biology to rapid development of vaccines and personalised therapeutics, where you might make a protein in a space of weeks to neutralise a rare genetic condition or an uncommon infection.
“Can we technically do it? The existing data says it’s not impossible, but we need to find out whether it’s economical and practical. There’s a lot of research directions we can take from here; it’s a good problem to have.”
This research was supported in part by grants from the Australian Research Council and the Deutsche Forschungsgemeinschaft.
Contact: Kirill Alexandrov - 07 3346 2017 or k.alexandrov@imb.uq.edu.au
Bronwyn Adams (IMB Communications) - 07 3346 2134 or 0418 575 247
