Physicochemical studies of non-histone protein HMG17 with DNA

Non-histone protein high mobility group-17 (HMG17) isolated from calf thymus consists of 89 amino acids and the complete sequence is known (Walker, J.M., Hastings, J.R.B. and Johns, E.W. (1977) Eur. J. Biochem. 176, 461-468). We have studied its conformation and interaction with DNA by a variety of technics. The results show that the protein has a random structure. It binds non-cooperatively, non-specifically and reversibly to DNA. It is estimated that each molecule of protein binds to 57 nucleotides of calf thymus DNA. The equilibrium constant for binding is approx. 1 - 10(6) M-1. HMG17 induces conformational changes in DNA similar to some of the histones in particular H1.