NASA Astrobiology Institute (NAI)

We have begun working on a highly sensitive method for detection of new RNA activities. The method, DICE, will be of use in evaluation of the RNA world hypothesis. In particular, DICE should complement the present means available, through selection-amplification, for isolation of rare catalytic activities in large randomized ribonucleotide sequence pools. This year we have acquired fluorogenic substrates suitable for DICE, based on a search of the literature. The substrates, intended for isolation of RNA proteases, have been tested with a model catalyst, highly purified trypsin. We have confirmed that these molecules are stable in the absence of specific catalysis, and that the fluorescence has the favorable low background reported in the literature. They are also readily hydrolyzed by the protein, and seem suitable for the next stage of the project, which is detection of activity using instrumentation suited to surveys of many randomized RNA molecules simultaneously.