Detection of nucleic acid-protein complexes by equilibrium ultracentrifugation.

Formation of complexes between yeast phenylalanine transfer RNA and phenylalanyl aminoacyl-transfer RNA synthetase is shown to occur under equilibrium conditions in the analytical ultracentrifuge. The technique of equilibrium sedimentation should be useful for the detection of transient associations between proteins and nucleic acids when only small amounts of unlabeled, but highly purified, materials are available.