Fig. 6.
Effects of extent of upstream DNA and αCTD on dissociation rates from lacUV5. The fraction of remaining open complexes is plotted as a function of time after addition of heparin. (A) Dissociation of native wild-type RNAP from lacUV5 fragments with upstream end points -130 (•), -100 (○), -63 (▿), or -45 (♦). Downstream end points were all +40. (B) Dissociation of reconstituted wild-type (•), αR265A (▿), and αΔ235 (♦) RNAPs from lacUV5 (-130 to +40). (C) kd values were derived from data shown and from a lacUV5 promoter fragment (-42 to +40) (data not shown), as described in Materials and Methods.