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

我的研究项目的重点是探索RNA和DNA的化学催化作用，这两种“核酸”是所有生物共有的遗传物质。诺贝尔奖得主的发现揭示了这些生物聚合物，长期以来被认为仅仅是作为储存和表达遗传信息的媒介，也可以催化代谢反应。我自己的研究小组使用不同的方法来尝试和定义这些由RNA和DNA组成的酶（“核酶”和“DNAzymes”）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，该假说认为，非常早期的生命形式使用核酸进行遗传和代谢目的；为了确定由这些生物聚合物制成的酶的功能如何，与蛋白质酶相对；生产用于临床、工业和生物医学研究的有用试剂；并认识到我们的催化rna和dna可能告诉我们它们在生物学中的可能作用。我的实验室用“体外选择”的方法定义了三种新的核酸酶：(1)结合和激活无处不在的细胞辅助因子血红素，以催化氧化化学的核酸酶；(2)一种“光解酶”DNAzyme，它利用光修复与癌症有关的DNA中由紫外线引起的损伤；(3)利用维生素B1的独特能力催化困难代谢反应的核酶。在一个令人惊讶的发展中，现在越来越清楚的是，这些新发现的催化特性中的一些实际上反映了RNA和DNA的基本特性，这些特性很可能在生物体中起作用。我建议使用多种生化、化学和生物学方法来研究上述目标。具体来说，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介导的损伤的特殊核苷酸序列。我们还将尝试定义利用血红素的核酶和DNAzymes能够催化的反应类别，以及它们与自然界自身的细胞色素P450酶的比较。并且，开发一种非常有前途的生化工具，我们已经确定用于探测血红素与RNA和DNA在活细胞内的相互作用，在疾病和健康的情况下。***除了其纯粹的科学目标外，我提出的研究项目将为高素质人才提供优秀而全面的培训，为他们在加拿大从事医学、生物技术和学术界以及其他各种职业选择奠定基础。

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.