Enzyme assemblys promoterrecognition, PoSsible catalytic subunits activator binding a BB′o Role unknown (not needed in vitro 5115511kDa a 35.5kDa Promoter U(3290kDa) specificit The e coli rna polymerase holoenzyme consists of six subunits:a2ββB0σThe E. coli RNA polymerase holoenzyme consists of six subunits: a2bb’ s. Possible catalytic subunits Promoter specificity Enzyme assembly, promoter recognition, activator binding Role unknown (not needed in vitro) 36.5 kDa 151 155 11 kDa (32-90 kDa)