The kinetics of the interaction of a helix-destabilizing protein from roe-deer liver with DNA and the influence of phosphorylation.

The kinetics of the interaction of the DNA double-helix-destabilizing protein from roe-deer liver with different DNAs revealed a fast phase which is observed both by the increase in A260 of the DNA and the quenching of the protein intrinsic fluorescence. A slow phase with a smaller amplitude is only recorded by the increase of A260.--The protein contains slightly less than two phosphate groups per molecule, removal of one of which by alkaline phosphatase does not affect its activity; however, removal of both phosphates decreases the DNA-unwinding property significantly. A similar decrease in activity is also revealed upon incorporation of an additional phosphate by cAMP-dependent protein kinase I.--Results of the protection of poly[d(A--T)] from DNase I digestion by the protein are in favor of a migration of the protein along the DNA.