Interactions of DNA with divalent metal ions. IV. Competitive studies of Mn2+ binding to AT- and GC-rich DNAs
✍ Scribed by Joseph Granot; Nuria Assa-Munt; David R. Kearns
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1982
- Tongue
- English
- Weight
- 690 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
It has been inferred from previous studies that Mn^2+^ ions bind preferentially to G·C base pairs in DNA, and it has even been suggested that this preference for G·C pairs might be responsible for some of the Mn^2+^ specific effects observed in various biochemical reactions. In this paper we investigate the AT/GC preference of Mn^2+^ by direct competition studies in which AT‐rich DNA was dialyzed against GC‐rich DNA in the presence of varying amounts of Mn^2+^. Analysis of these results demonstrates that over a wide range of Mn^2+^/DNA(P) molar ratios, Mn^2+^ binds to A·T and to G·C base pairs with virtually identical affinity, although in a somewhat different mode. Both the present and previous nmr, uv, CD, and melting studies are discussed in terms of the different modes of binding of Mn^2+^ to single‐ and double‐stranded DNA.