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

我的研究计划的主旨是探索RNA和DNA可用的化学催化宇宙，这两种“核酸”是所有活着的有机体共有的遗传物质。诺贝尔奖获得者的发现揭示了这些生物聚合物也可以催化新陈代谢反应。长期以来，这些生物聚合物被认为只作为存储和表达遗传信息的试剂。我自己的研究小组使用不同的方法来尝试和定义这种由RNA和DNA组成的酶(“核酶”和“DNA酶”)确实可以催化什么反应。我们的目标有四个：测试强大的“RNA世界假说”的有效性，该假说假设非常早期的生命形式将核酸用于遗传和代谢目的；定义由这些生物聚合物制成的酶相对于蛋白质酶的功能有多好；生产用于临床、工业和生物医学研究的有用试剂；以及认识催化RNA和DNA可能告诉我们它们在生物学中的可能作用。我的实验室使用“体外选择”的方法定义了三类新的核酸酶：(1)结合并激活普遍存在的细胞辅因子--血红素以催化氧化化学的那些酶；(2)利用光来修复与癌症相关的DNA中紫外线诱导的损伤的“光解酶”DNAzyme；以及(3)利用维生素B1的独特能力催化困难的代谢反应的核酶。令人惊讶的是，现在越来越清楚的是，这些新发现的催化性质中的一些实际上反映了RNA和DNA的基本性质，这些性质可能在生物体内发挥作用。*我建议使用各种生化、化学和生物方法来研究上述目标。具体地说，我们将使用体外选择的方法来测试由RNA或DNA制成的光解酶是否可以与蛋白质光解酶的催化能力相媲美；并严格确定标准的双螺旋DNA中是否存在特别抵抗紫外线光损伤的特权核苷酸序列。我们还将试图定义利用血红素的核酶和DNAzyme能够催化的反应类别，以及它们与自然界自己的细胞色素P450酶的比较。而且，开发一种非常有希望的生化工具，我们已经确定，可以探测血红素与活细胞内的RNA和DNA的相互作用，无论是在疾病中还是在健康的环境中。*除了其纯粹的科学目标外，我提议的研究计划还将为高素质的人员提供出色和全面的培训，为他们在医学、生物技术和学术界以及加拿大其他各种职业选择中的职业生涯做好准备。

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.