DNA-binding domain of GCN4 induces bending of both the ATF/CREB and AP-1 binding sites of DNA

AUTOR(ES)
FONTE

Oxford University Press

RESUMO

The interaction of proteins with DNA results, in some cases, in DNA bending, and this might have functional importance. However, when the protein-induced bending of DNA is small, its measurement presents a problem. It is shown that the fluorescence resonance energy transfer between fluorophores placed on the ends of the specially designed U-shaped DNA, which contains the DNA-binding sites at its central part, can be successfully used for this purpose. The lever effect of the arms of such U-shaped DNA ensures that the distance between the fluorophores is very sensitive to bending of the central part. Using this technique, it was shown that (i) the AP-1 and ATF/CREB binding sites of GCN4 transcription factor are pre-bent to the same extent (∼12° toward the major groove) and (ii) binding of the GCN4 DNA-binding domain (GCN4-bZIP) results in additional bending of both these target sites but to a greater extent at the ATF/CREB site. In total, in the complex with GCN4-bZIP, the ATF/CREB site is bent by (25 ± 2)° and the AP-1 site by (20 ± 2)° toward the minor groove.

Documentos Relacionados