Identification and purification of the Lon+ (capR+) gene product, a DNA-binding protein

The polypeptide product of the lon (capR) gene was identified and partially purified from bacterial strains homozygous for the capR(+) or capR9 (ochre mutation) alleles cloned with pSC101. A 94,000-dalton polypeptide was identified as the lon (capR) gene product. Studies of binding to DNA cellulose columns and nitrocellulose filters indicate that the capR(+) and capR9 proteins bind DNA.