{'fraction_non_alphanumeric': 0.02799650043744532, 'fraction_numerical': 0.0, 'mean_word_length': 5.285714285714286, '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}}
ClpS is the recognition component for Escherichia coli substrates of the N‐end rule degradation pathway

The N‐end rule degradation pathway states that the half‐life of a protein is determined by the nature of its N‐terminal residue. In Escherichia coli the adaptor protein ClpS directly interacts with destabilizing N‐terminal residues and transfers them to the ClpA/ClpP proteolytic complex for degradation. The crucial role of ClpS in N‐end rule degradation is currently under debate, since ClpA/ClpP was shown to process selected N‐terminal degrons harbouring destabilizing residues in the absence of ClpS. Here, we investigated the contribution of ClpS to N‐end rule degradation by two approaches. First, we performed a systematic mutagenesis of selected N‐degron model substrates, demonstrating that ClpS but not ClpA specifically senses the nature of N‐terminal residues. Second, we identified two natural N‐end rule substrates of E. coli: Dps and PATase (YgjG). The in vivo degradation of both proteins strictly relied on ClpS, thereby establishing the function of ClpS as the essential discriminator of the E. coli N‐end rule pathway.