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

A fraction of low mobility group (LMG) nonhistone protein designated LMG(160) 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 LMG(160) 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 LMG(160) 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 LMG(160) protein preferentially binds to double stranded DNA destabilizes it and the binding is electrostatic.