Conformation of DNA in solution: CD calculations based on crystal structures of B- and Z-DNA fragments
✍ Scribed by Daniel E. Callahan; Thomas M. Hooker Jr.
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1987
- Tongue
- English
- Weight
- 350 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
CD is a sensitive and widely used spectroscopic technique for monitoring DNA conformational changes in Even though CD spectroscopy has made valuable contributions toward our understanding of the structure of DNA, the theoretical basis of the CD spectra observed for DNA in its various conformations has not been completely
Recent singlecrystal x-ray difiaction studies on B-DNA fragments have produced coordinates at atomic resolution?-" katini et al." have undertaken a detailed analysis of the structural differences found in three crystal variants of d(CGCGAAT-"CGCG) and its 9-Br derivative. The double helix was found to be bent in d(CGCGAA"CGCG), referred to as the "native" structure, and in the 9-Br derivative in 60% methylpentanediol at 20°C, referred to as "MPD 20." On the other hand, the helix was found to be straight in the case of the 9-Br derivative at 7"C, referred to as "MPD 7." These single-crystal structures show sequence-specific variations in local helix parameters that differ somewhat from the classical model of B-DNA."-l3
Coordinates obtained from these crystal structures have usually given results inferior to those obtained with the classical model when used for CD or nmr calculation^.^*'^ This has led many investigators to conclude that the solution conformation of DNA is a more regular, idealized structure than the single-crystal structures.