{'fraction_non_alphanumeric': 0.029411764705882353, 'fraction_numerical': 0.0058823529411764705, 'mean_word_length': 5.462025316455696, '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}}
Trans‐dominant mutations in the 3′‐terminal region of the rpoB gene define highly conserved, essential residues in the β subunit of RNA polymerase: the GEME motif

The multimeric DNA‐dependent RNA polymerases are widespread throughout nature. The RNA polymerase of Escherichia coli, which is the most well characterized, consists of a holoenzyme with subunit stoichiometry of α2ββ′σ. The β subunit is conserved and has been implicated in all stages of transcription. The extreme C‐terminus of the β subunit, which includes two well‐conserved sequence segments, contributes to the active centre and has been proposed to act in transcriptional termination. We describe a genetic system for further characterizing the role of the extreme C‐terminus of the β subunit of E. coli RNA polymerase. This involves random, PCR (Polymerase Chain Reaction)‐mediated mutagenesis of the 3′ region of rpoB encoding the C‐terminal 116 amino acids of β, followed by the isolation and characterization of trans‐dominant‐negative mutations.