Catalytic nucleic acids that highlight surprising fundamental properties of DNA and RNA

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The thrust of my research program is to explore the universe of chemical catalysis available to RNA and DNA, the "nucleic acids" that are the shared genetic material of all living organisms. Nobel-winning discoveries have revealed that these biopolymers, thought for long to operate solely as agents for storing and expressing genetic information, can also catalyze metabolic reactions. My own research group uses varied methodologies to try and define what reactions such enzymes made out of RNA and DNA ("ribozymes" and "DNAzymes") can indeed catalyze. Our goals are fourfold: to test the validity of the powerful "RNA World Hypothesis", which posits that very early life forms used nucleic acids for both genetic and metabolic purposes; to define how well enzymes made from these biopolymers can function, vis-a-vis protein enzymes; to generate useful reagents for application in the clinic, in industry, and in biomedical research; and, to recognize what our catalytic RNAs and DNAs may be telling us about their possible roles in biology. My lab has used the methods of "in vitro selection" to define three new classes of nucleic acid enzymes: (1) those that bind and activate the ubiquitous cellular cofactor, heme, to catalyze oxidative chemistry; (2) A "photolyase" DNAzyme, that harnesses light to repair UV-induced lesions in DNA linked to cancer; and (3) a ribozyme that utilizes the unique capabilities of vitamin B1 to catalyze a difficult metabolic reaction. In a surprising development, it is now becoming clear that some of these newly identified catalytic properties actually reflect fundamental properties of RNA and DNA, that are likely in operation in living organisms. *** I propose to use a variety of biochemical, chemical, and biological approaches to investigate the above-stated goals. Specifically, we will use the methods of in vitro selection to test whether a photolyase enzyme made out of RNA or DNA can rival the catalytic prowess of protein photolyase enzymes; and, to determine rigorously whether there are privileged nucleotide sequences within standard, double-helical DNA that are particularly resistant to UV light-mediated damage. We will also attempt to define the classes of reactions that heme-utilizing ribozymes and DNAzymes are capable of catalyzing, and how they compare to nature's own Cytochrome P450 enzymes. And, develop a very promising biochemical tool that we have identified for probing heme's interaction with RNA and DNA within living cells, in disease as well as in healthy contexts. *** In addition to its purely scientific goals, my proposed research program will provide excellent and rounded training for highly qualified personnel, to set them up for careers in medicine, biotech, and academia, as well as in diverse other careers options in Canada.