期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：6
页码：2746-2751
DOI：10.1073/pnas.96.6.2746
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Nearly 50 individual DNAs with polynucleotide kinase-like activity were isolated from a random-sequence pool by using in vitro selection. Each self-phosphorylating deoxyribozyme makes use of one or more of the eight standard NTPs or dNTPs as a source of activated phosphate. Although most prototypic deoxyribozymes poorly differentiate between the ribose and deoxyribose moieties, further optimization by in vitro selection produced variants that display up to 100-fold discrimination between related NTP and dNTP substrates. An optimized ATP-dependent deoxyribozyme uses ATP >40,000-fold more efficiently than CTP, GTP, or UTP. This enzyme operates with a rate enhancement of nearly one billion-fold over the uncatalyzed rate of ATP hydrolysis. A bimolecular version of the ATP-dependent deoxyribozyme was further engineered to phosphorylate specific target DNAs with multiple turnover. The substrate-recognition patterns and rate enhancements intrinsic to these DNAs are characteristic of naturally occurring RNA and protein enzymes, supporting the hypothesis that DNA has sufficient catalytic potential to function as an enzyme in biological systems.
