Estudos sobre a estabilidade e estrutura do DNA atraves da fotofisica de corantes intercalados

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

In this work one used intercalated and fluorescent dyes to probe alterations in the DNA structure due to change in its environment, using absorption and emission spectroscopy. Some of these alterations can be attributed to dipolar interactions between different dyes that are responsible for energy transfer. This process can be used to obtain the distance among those probes. The variables used in this work were the presence of NaCI, guanidinium hydrochloride (GuCI), pressure and GuCl/pressure. The variation in the NaCI concentration causes a different effect from that observed for GuCI. NaCI alters the balance among the intercalated and aggregated species of the probes, while with the GuCI that doesn t happen. The spectral characteristics observed in the presence of GuCI are different for the free and intercalated species in aqueous solution, result of different interactions between the dyes and DNA, associated to a desestruturation of that macromolecule. The pressure doesn t change the balance among the intercalated and free species in the absence of GuCI. However, in presence of this salt the increase of the pressure induces the return of the spectral characteristics of the inserted probe in DNA, attributed to the structural recovery of the intercalation sites. When a pair of donor and acceptor of energy is used and one increase the pressure it is observed an alteration in the efficiency of energy transfer associated to a close proximity of the dyes.

ASSUNTO(S)

energia

ACESSO AO ARTIGO

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