Sulfur-containing nucleic acids: Synthesis, chemical reactions in supramolecular biopolymer complexes, biological applications

The chemical behavior of sulfur-containing oligonucleotides and their react ivity in self-assembled nucleic acids (NA) and specific NA-protein complexe s is considered. Reviewed are postsynthetic approaches that allow introduci ng sulfur-containing linkages at preselected positions of the sugar-phospha te backbone of DNA and between neighboring nucleobases, to incorporate disu lfide bridges between complementary strands of double- and triple-stranded DNAs, in large catalytic RNA, etc. Special reference is given to the site-s pecific chemical modifications as a tool for elucidating the structure, fol ding, and function of biomolecules. Structure-directed chemical reactions a re shown to be helpful in detecting point mutations in DNA, targeting the m odifications on specific positions of NA, probing the molecular recognition in protein-DNA interfaces, studying the conformational dynamics of nucleic acids, and discriminating between different folding models.