Nonintercalative binding of ethidium bromide to nucleic acids: crystal structure of an ethidium--tRNA molecular complex.

Abstract
X-ray diffraction studies at 4.5-.ANG. resolution on crystals of a complex of ethidium bromide and yeast phenylalanine tRNA reveal a nonintercalative mode of binding of the ethidium within the tertiary structure. This is contrary to the expected intercalative binding to the double-helical regions.