DNA-BINDING OF POLYOMAVIRUS LARGE T-ANTIGEN - KINETICS OF INTERACTIONS WITH DIFFERENT TYPES OF BINDING-SITES

Polyomavirus large T-antigen binds to GRGGC sites in double-stranded v iral DNA, regulating transcription and replication, Using surface plas mon resonance to record interactions of large T-antigen with different types of binding sites, we found that the configuration of recognitio n motifs influenced both the association and dissociation rates, Parti cularly, the complex formed at the origin of DNA replication was labil e, A comparison of the interactions between targe T-antigen and bindin g sites with one, two and four GRGGC motifs in tandem showed a strong preference for dimer binding, without detectable co-operativity betwee n dimers, Sodium chloride stabilised the complexes, whereas the dissoc iation increased rapidly by increasing pH above 7.0. (C) 1998 Federati on of European Biochemical Societies.