Formation of ψ(+) and ψ(−) DNA

✍ Scribed by Y. A. Shin; G. L. Eichhorn

• Book ID: 102763631
• Publisher: Wiley (John Wiley & Sons)
• Year: 1984
• Tongue: English
• Weight: 543 KB
• Volume: 23
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360230211

✦ Synopsis

Synopsis

DNA molecules can be organized into ordered aggregates of opposite handedness by complexation with polylysine and other polypeptides; we have investigated the conditions under which $(+) and $(-I structures are produced with double-helical synthetic polynucleotides.

Both poly(dGdC)-poly(dGdC) and poly(dAdT)-poly(dAdT) readily form $( -) structures with polylysine, although the method of preparation can alter the CD spectra. The GC copolymer, which is more susceptible to conversion into A or 2 conformers, forms $(+) structures with lysine-alanine copolypeptides more readily than the AT copolymer. Nucleotide base modifications that favor the Z structure, such as bromination and methylation, also favor $(+) formation, and the Co(NH3)&13 reagent that readily induces the Z structure also leads to $(+). Thus, the production of the $(+) structure seems to be frequently correlated with susceptibility to A or Z formation, although there are some cases in which the B conformer also leads to $(+). Polyethylene glycol generally produces a #(-) structure; the differentiation between $(+I and $(-I structures seems to require electrically charged polymers.