Mechanism of RNA-protein interactions in tobacco mosaic virus: analysis of the pH stability of virus protein complexes with synthetic polynucleotides.

TMV-like RNP complexes were reconstituted from TMV protein and synthetic polynucleotides. Analysis of the pH stability of RNP 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 -NH-CO-groups of U and G are involved in hydrogen bonding with protein. It is suggested that TMV protein has two U- and one G-specific binding sites which, according to the phase position of the protein subunits relative to the origin of TMV assembly (D.