ABSTRACT
Vital cellular processes including genome replication, transcription, translation, and repair rely on speci c interactions between proteins and nucleic acids to complete diverse and complex tasks. Among the biophysical techniques employed to study the large biomolecular assemblies performing these tasks, mass spectrometry (MS) presents the greatest potential based on its intrinsic characteristics and accessible information. Ever since the initial reports describing the ability of electrospray ionization (ESI)1,2 to desorb intact noncovalent complexes,3-5 ESI-MS has been successfully applied to the characterization of a large variety of assemblies, as extensively reviewed in references.6-9 In this chapter, we offer an account of our personal experience in employing this analytical platform for the functional investigation of selected protein-nucleic acid complexes of retroviral systems. The strategies followed in these types of studies, the practical issues faced in completing the experiments, and the information provided by the different approaches are discussed in the context of the recent advances in the mass spectrometric analysis of protein-nucleic acid complexes.
