DNA از بافت كبد موش و ميانكنش آن با LMG جداسازي پروتيين

ISOLATION OF A FRACTION OF PROTEIN FROM RAT LIVER AND ITS INTERACTION WITH DNA

In eukaryote cells, DNA is complexed with a series of basic proteins making units of chromatin structure named nucleosomes. In addition, nonhistone proteins with different function are the components of chromatin. Among these proteins, a group with a low mobility on gel clectrophoresis have been identified and named LMG. In this study a LMG protein with a molecular weigh of 160 kd. Was isolated from rat liver by preparative gel electrophoresis and electroelution techniques. The interaction of this protein with DNA was investigated using uv/vis spectroscopy and single and double stranded DNA-cellulose affinity chromatography. The results show that the binding of purified LMG protein to DNA increased absorbance of DNA at 210 and 260 nm. The affinity of LMG to double stranded DNA was higher than single stranded DNA. From the results presented above, it is concluded that LMG is a possibly regulatory protein in which by its interaction unwinds DNA molecule and may participate in some DNA functions such as transcription and replication.