{'fraction_non_alphanumeric': 0.03749098774333093, 'fraction_numerical': 0.0418168709444845, 'mean_word_length': 5.11453744493392, '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}}
Identification of a common epitope in the sequences of COL4A1 and COL6A1 recognized by monoclonal antibody #141

Identification of a type IV collagen α1 polypeptide in non-triple helical form [NTH α1(IV)], possibly involved in angiogenesis, introduces the further possibility of the existence of non-triple helical forms of other collagen chains. We previously reported that an anti-NTH α1(IV) monoclonal antibody #141 recognizes not only NTH α1(IV) but also a novel non-triple helical collagen polypeptide NTH α1(VI) encoded by COL6A1. In this study, we identified the recognition sequence in order to better understand the properties of antibody #141 and provide clues regarding the biological function of the two non-triple helical molecules. Additionally, we determined the common epitope between COL4A1 and COL6A1 as PXXGXPGLRG, with surface plasmon resonance analyses revealing KD values for the COL4A1 epitope as 5.56±1.81×10-9 M and for the COL6A1 epitope as 7.15±0.44×10-10 M. The specific recognition of NTH α1(IV) and NTH α1(VI) by antibody #141 can be explained by the common epitope sequence. Moreover, epitope localization supports previous finding that NTH α1(IV) and NTH α1(VI) differ in conformation from the α1 chains in triple-helical type IV and type VI collagen. These findings suggest that antibody #141 might be useful for diagnosis of type VI collagen myopathies.