Interaction of a low mobility group protein,LMG160, with deoxyribonucleic acid

A fraction of low mobility group (LMG) nonhistone protein designated LMG₁₆₀ was isolated from rat liver chromatin by preparative gel electrophoresis and its interaction with DNA was studied using thermal denaturation and DNA–cellulose affinity chromatography techniques. The results showed that LMG₁₆₀ with an isoelecteric point of 5–5.5 was bound to DNA and decreased its melting temperature. Increasing ionic strengths decreased this effect. DNA–cellulose affinity chromatography showed the affinity of LMG₁₆₀ to double stranded DNA was higher than that to single stranded DNA, since it required 0.6 M NaCl for elution. The results suggest that LMG₁₆₀ protein preferentially binds to double stranded DNA destabilizes it and the binding is electrostatic.