{'fraction_non_alphanumeric': 0.035653650254668934, 'fraction_numerical': 0.008488964346349746, 'mean_word_length': 5.01530612244898, '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}}
Activation of protein splicing by protease- or light-triggered O to N acyl migration.

Intramolecular O-N acyl migrations are well known reactions in organic chemistry[1-3]. This type of rearrangement has been the object of renewed interest in the field of chemical biology as it provides opportunities for the spatial and temporal control of peptide conformation and function.[4, 5] Incorporation of an O-acyl isomer of a peptide bond at a serine or threonine residue in a peptide sequence (herein referred to as an O-acyl linkage) introduces a kink into the main chain of the biopolymer and interrupts the normal backbone hydrogen-bonding characteristics, both of which can affect structure and function.[5-7] In the case where the Ser/Thr α-amino group is transiently protected, recovery of the normal amide backbone and, as a consequence, native structure and function, can be achieved by removal of this protecting group, thereby triggering the spontaneous O-N acyl shift. Accordingly, a variety of triggers of O-N acyl migrations have been developed that allow the restoration of native structure following the administration of light,[8] pH,[9] or enzymatic activity.[10]