Specific A . T DNA sequence binding of RP-HPLC purified HMG-I

HMG-I (alpha-protein) is a high mobility group protein which recognizes and binds specifically to A . T rich double stranded DNA. We have investigated, by electrophoretic shift assays and DNase I footprinting, the ability of reverse-phase high performance liquid chromatography purified HMG-I to bind to specific A . T rich duplex DNA sequences. We show here that when HMG-I is isolated and purified under denaturing conditions it retains its specific A . T DNA binding activity. These results suggest that reverse-phase high performance liquid chromatography to be the method of choice for the preparation of HMG-I.