Estudo da interação DNA-HOESCHT (33258) por pinçamento ótico

• Autor(a) principal: Silva, Eduardo Ferreira da
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4267
• topic: DNA-HOESCHT; Pinçamento ótico; Modelo de cadeia vermiforme; DNA-HOESCHT; Optical clamping; Wormlike chain model; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA

By performing single molecule stretching experiments with optical tweezers, we have stu- died the DNA interaction with the ligand Hoechst(33258). The mechanical properties of the complexes as a function of ligand concentration were directly determined from these measure- ments by fitting the force versus extension curve to the WormLike Chain model of semiflexible polymers. In addition, the physico-chemical parameters of the interaction were extracted from the persistence length data by using a previously developed two-sites quenched disorder sta- tistical model, allowing the determination of the binding isotherm. This model has allowed us to decouple the two different binding modes present in this system. In particular, it was found that the binding isotherm consists of two Hill-type processes, one non-cooperative and the other strongly cooperative. Finally, DNA condensation due to the interaction with the ligand was also verified and characterized here by analyzing the apparent contour length of the complexes.