B-Z DNA reversible conformation changes effected by high pressure.
FEBS Lett
; 279(1): 1-4, 1991 Feb 11.
Article
em En
| MEDLINE
| ID: mdl-1995328
ABSTRACT
There are numerous data showing that a DNA molecule with alternate pirymidine-purine sequence can adopt a left-handed, double-helical Z-DNA conformation. Such structural changes of DNA occur as a consequence of environmental conditions (e.g. 4 M NaCl) or chemical modification (e.g. methylation or bromination of bases). In this paper, we found for the first time that high pressure (several kilobars) can change the DNA conformation from the B to the Z form. When the pressure is reduced to an atmospheric one, DNA conformation returns back to the B-form. The Z-DNA structure formation was confirmed by circular dichroism (CD) and ultraviolet (UV) measurements. However, we found, that the values of the ratio of absorbance at the wavelengths 295 and 257 nm in the range of 0.3-0.4 is not a fully conclusive proof for the Z-DNA conformation. Although the ratio is typical for Z-DNA form, it is not obvious that the negative band in CD spectrum will be observed. On the other hand, methylated DNA does not undergo B----Z DNA transitions at the high pressure. These conformational changes of DNA molecules could be interpreted as the effect a of different hydration of various DNA forms.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pressão
/
DNA
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
1991
Tipo de documento:
Article