[Structure of chromosomal deoxyribonucleoproteins. XI. Organization of deoxyribonucleoprotein complex in bacterial...

Isolation of bacterial chromosomes under "mild" conditions enable us to purify a bacterial deoxyribonucleoprotein (DNP). This DNP is enriched in small basic proteins which are complexed with DNA throughout all the purification steps. The basic proteins are shown to be similar to some heat-resistant proteins of cellular extract and can interact with DNA in vitro. Extensive nuclease digestion of purified DNP of E. coli produced the smallest DNA fragments of 100--120 base pairs in length. The proteins of the DNP and the possible mode of arrangement of basic proteins along the DNA are discussed.