{'fraction_non_alphanumeric': 0.023423423423423424, 'fraction_numerical': 0.01021021021021021, 'mean_word_length': 4.725085910652921, '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}}
Nucleic Acids Research Mechanism of RNA-protein interactions in tobacco mosaic vims: analysis of the pH stability of virus protein complexes with synthetic polynucteotides

TMV-like RHP complexes were reconstituted from TMV protein and synthetic polynucleotides. Analysis of the pH stability of RHP with polynucleotides containing U, G, or their analogues reveals a correlation between the stability of their structure and the pK values of the bases, and indicates that the -HH-CO-groups of U and G are involved in hydrogen bonding with protein. It is suggested that TMV protein has two Uand one G-specific binding sites which, according to the phase position of the protein subunits relative to the origin of TMV assembly (D. Zimmern (1977), Cell 11, 463) are likely to be organized as UGU. The binding of the A and C residues of RNA with TMV protein is nonspecific. TMV protein groups with pK 6.3, 7.5 and 9.7 were found to be essential in the proteinprotein interactions in RHP. A group of the protein with pK 8.2 is also involved in RHP stabilization. Both protein-protein interactions and interactions of protein with RHA phosphate groups were shown to be mediated by a conformational change in the protein induced by base binding. The effect of bases on both types of interactions changes in the order G*=U» »A, and incorporation of G in RHP proceeds in a compulsory way at the expense of interaction of the neighbouring nucleotide residues in polynucleotides with protein. The data obtained are used to discuss the principles of the cooperativity of the interactions between TMV components and the mechanism of initiation and elongation in TMV self-assembly.