Circular dichroism of acridine orange bound to DNA

摘要: The circular dichroism (CD) spectra of DNA–acridine orange (DNA–AO) complex in the visible region were measured at DNA phosphate-to-dye ratios (P/D) from 1 to 550. CD spectrum DNA–AO P/D ratio between and approximately 40 consists four components, i.e., positive bands centered 510 480 mμ, negative 497 468 mμ. mμ are optimum = 4, change e1 − er with suggests that both them induced interaction dye molecules bound adjacent binding sites, each which is composed nucleotides. This supported by fact values for decrease increasing temperature or methylene blue concentration added complex. Cotton effect at, most favored larger (∼8), suggested assignment two an empty site them. A observed less than 4 1. Above 40, can not be resolved into its components even sufficiently high (550) shows a small effect.