{'fraction_non_alphanumeric': 0.02212705210563883, 'fraction_numerical': 0.010706638115631691, 'mean_word_length': 5.6761904761904765, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
In vitro selection and characterization of a novel Zn(II)-dependent phosphorothiolate thiolesterase ribozyme.

Here we present the in vitro selection of a novel ribozyme specific for Zn2+-dependent catalysis on hydrolysis of a phosphorothiolate thiolester bond. The ribozyme, called the TW17 ribozyme, was evolved and selected from an artificial RNA pool covalently linked to a biotin-containing substrate through the phosphorothiolate thiolester bond. The secondary structure for the evolved ribozyme consisted of three major helices and three loops. Biochemical and chemical studies of ribozyme-catalyzed reaction products provided evidence that the ribozyme specifically catalyzes hydrolysis of the phosphorothiolate thiolester linkage. A successful ribozyme construct with active catalysis in trans further supported the determined ribozyme structure and indicated the potential of the ribozyme for multiple-substrate turnover. The ribozyme also requires Zn2+ and Mg2+ for maximal catalysis. The TW17 ribozyme, in the presence of Zn2+ and Mg2+, conferred a rate enhancement of at least 5 orders of magnitude when compared to the estimated rate of the uncatalyzed reaction. The ribozyme completely lost catalytic activity in the absence of Zn2+, like Zn2+-dependent protein hydrolases. The discovery and characterization of the TW17 ribozyme suggest additional roles for Zn2+ in ribozyme catalysts.