Influence of Cations on Secondary Structures of Macromolecules and Membranes - IR Investigations

摘要: In the IR spectra coupling of vibrations leads to band splitting and bands shifting in opposite directions, thus providing information on orientation groupings macromolecules relative each other. — With polynucleotides base pairing is indicated by such effects with C=O stretching vibrations. ribo(polynucleotides) 2’OD bending vibration C—O—C ether group ribose residues proves that may be cross-linked via hydrogen bonds, which are formed groups O atom neighboring residues. These H-bonds stiffen backbone RNA, inducing, for instance homoribo (polynucleotides) neutral medium, rod-like structures. The influence cations discussed. Two conformations observed: (a) Open image new window can turned outward at backbone. (b) toward latter induced strong fields. - It shown conformation Mg2+ poly(U) probably a triple not double helix. Melting structure t·RNA Phe temperature dialysis against distilled water ions increase melting 40°C. This effect preferentially caused change tertiary secondary structure. contrast this result, 23 S RNA helical regions become more compact bonds between 2’OH residues, due ions.