A breakthrough in synthetic biology has opened the door to a new way of treating incurable illnesses such as cancer and Ebola, and could shed light on the origins of life or even the possibility of extraterrestrial life on other planets.
For the first time, researchers have made synthetic enzymes – the vital ingredients needed for life – from artificial genetic material that does not exist outside the laboratory. The milestone could soon lead to new ways of developing drugs and medical treatments.
The findings are the latest in the field of synthetic biology, which attempts to create new biological molecules and even novel life-forms capable of carrying out a range of important medical and industrial functions, from manufacturing pharmaceuticals to detoxifying polluted land.
“Synthetic biology is delivering some truly amazing advances that promise to change the way we understand and treat disease,” said Professor Peter Maxwell, chair of the cellular medicine board of the Medical Research Council (MRC), which funded the study.
“The UK excels in this field and this latest advance offers the tantalising prospect of using designer biological parts as a starting point for an entirely new class of therapies and diagnostic tools that are more effective and have a longer shelf-life,” Professor Maxwell said.
The discovery, by scientists at the MRC Laboratory of Molecular Biology in Cambridge, also widens the scope for finding extraterrestrial life-forms on other planets based on completely different biochemistry to that used by life on Earth.
“When we look for life elsewhere, either in the Solar System or on exoplanets beyond, this discovery means that we may have to widen the boundaries of the conditions where we think life may exist,” said Philipp Holliger, who led the MRC research team.
“It expands the chemical range that one can envisage life living in. It would potentially widen the number of exoplanets that one could consider would be hospitable for some form of life,” Dr Holliger said.
Alex Taylor, the lead author of the study, said: “The [discovery] raises the possibility that, if there is life on other planets, it may have sprung up from an entirely different set of molecules, and it widens the possible number of planets that might be able to host life.”
The synthetic enzymes were able to cut and paste pieces of artificial genetic material known as “XNA”, which does not exist in nature. XNA is able to store and replicate genetic information, just like its two natural equivalents DNA and RNA, and was synthesise in Dr Holliger’s lab three years ago.
The enzymes were themselves made from folded strands of XNA molecules. This extra enzymatic property of the artificial genetic material mimics the natural RNA enzymes found in many organisms, including humans, the scientists said.
“Until recently, it was thought that DNA and RNA were the only molecules that could store genetic information and, together with proteins, the only biomolecules able to form enzymes,” Dr Holliger said.
“Our work suggests that, in principle, there are a number of possible alternatives to nature’s molecules that will support the catalytic processes required for life. Life’s ‘choice’ of RNA and DNA may just be an accident of prehistory chemistry,” he said.
The “XNAzymes” carried out simple enzymatic reactions like cutting and joining RNA strands in a test tube. They were also able to join XNA strands together, which represents one of the first steps in creating a replicating biological system, Dr Holliger said.
The technology could be developed to make drugs that can block cancer-causing genes or bind to the RNA of viruses such as Ebola or HIV.
“It may be possible to design therapeutic XNA molecules that can cleave to an oncogene [cancer gene] or to viral RNA, and because XNA does not exist in nature it will not be broken down quite so fast as DNA or RNA which means it will work for longer,” Dr Holliger said.
“Our XNAs are chemically extremely robust and, because they do not occur in nature, they are not recognised by the body’s natural degrading enzymes. This might make them an attractive candidate for long-lasting treatments that can disrupt disease-related RNA,” he said.