NSF Award
2114588
This project enables biologists to reach “through the looking glass” to construct and manipulate the mirror-image counterparts of the genetic molecules of life — the nucleic acids DNA and RNA. Complex molecules and their mirror-images are structurally distinct, like left and right hands, a property known as chirality. The biomolecules found in all known life on Earth are homochiral, consisting exclusively of left-handed proteins and right-handed nucleic acids. The mirror-images of these biomolecules, such as left-handed nucleic acids, are neither made nor recognized by the machinery of the cell. This property can be exploited to provide synthetic materials that are resistant to biological disruption and can be engineered to interact with their biological counterparts across the mirror for use in biotechnology and medicine. In this project, tools are being developed to synthesize unnatural left-handed nucleic acids, using recently developed right-handed nucleic acid enzymes. These “cross-chiral” enzymes also are being used to study why life as we know it is homochiral, and whether life that functions on both sides of the mirror is possible. The aim is to expand the reach of synthetic biology across the mirror, providing robust methods to generate mirror-image biomolecules, which will be made widely available to other researchers. This project is also training a diverse set of undergraduate, graduate, and postdoctoral scientists to use cross-chiral biology in their own research and will cultivate the next generation of scientists through a hands-on laboratory experience for high school students in chiral biology, encouraging their exploration of STEM fields.<br/><br/>The research builds on a toolkit of cross-chiral RNA enzymes, or “ribozymes”, that catalyze the synthesis of RNA polymers of the opposite handedness. New techniques for the directed evolution of polymerase ribozymes are being used to provide generalized methods for the synthesis of L-RNAs from simple and readily available starting materials and to amplify those L-RNAs using a cross-chiral form of the polymerase chain reaction (PCR). This toolkit will enable the construction of adaptive genetic systems that function in a fundamentally different way than known biology, addressing the meta-biological rules for how macromolecules of opposite handedness can interact to support enzymatic catalysis, genetics, and evolution. In parallel, the cross-chiral toolkit enables the scalable preparation of complex L-RNAs having a user-defined sequence, as exemplified by the synthesis of functional mirror-images of the RNA machinery of the cell. Molecular and synthetic biology have benefited from the progressive development of tools to manipulate the microscopic world, and the tools developed here aim to demonstrate that, likewise, there is plenty of room across the mirror.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
