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Project Progress

RNA world and origin of life (dm)

We explored fluor systems for use in the DICE (Direct Isolation of Catalysts or Enzymes) ribozyme isolation procedure. concluding that the initial methods proposed are very difficult and might require development of new single-molecule-detection technology. Therefore, we have switched to the immobilization of RNAs to be tested on agarose beads, along with a substrate that can be converted to a new product if the nearby RNAs include a ribozyme activity. The amplification needed to detect a few turnovers by the RNA enzyme is achieved by linking a second highly fluorescent bead specifically to areas where the product has been created. The bead carrying the active RNA is now a multi-bead system and highly fluorescent, and can be sorted out on a Fluorescence Activated Cell Sorter (FACS) machine, which is a type of standard biomedical lab technology

A new project has been added: we have synthesized new Transition State Analogues (TSA) for the ribosomal peptidyl transferase ribozyme, and begun a set of selections for RNAs that bind these compounds. Use of previous TSAs synthesized in our laboratory has led to the identification of the peptidyl transferase (enzyme that forms peptide bonds in proteins) on the ribosome as an RNA enzyme and provided a substantial argument that the peptidyl transferase has been an RNA since the origin of protein biosynthesis in the RNA world. These new selections will hopefully show that the peptidyl transferase itself (or some close relative) can emerge directly from randomized RNA sequences. This would strongly confirm one of the primary predictions of the RNA world hypothesis, and accordingly support the hypothesis that RNA organisms were out immediate ancestors on Earth.