STUDIES ON THE OMEGA-SUBUNIT OF ESCHERICHIA-COLI RNA-POLYMERASE - ITSROLE IN THE RECOVERY OF DENATURED ENZYME-ACTIVITY

Highly purified Escherichia coli RNA polymerase contains a small subun it termed omega that has a molecular mass of 10105 Da and is comprised of 91 amino acids, To elucidate the function of omega, whose role is as yet undefined, the subunit was purified to over 95% purity from an overproducing strain [BL21 (pGP1-2, pE3C-2)]. Purified omega was then reconstituted with RNA polymerase isolated from an omega-less mutant. Externally added omega inhibited promoter-specific transcriptional act ivity at all promoters tested. Renaturation of fully denatured omega-l ess RNA polymerase in the presence of excess omega yielded maximum rec overy of activity suggesting a structural rather than functional role for omega.