the activation of t , he lac promoter and arnC ' B. 4 I ) 1 ) ~ CRP is similar in that CRT ' shows the S ~ IIIP orientation tlependcnce in both operons : as in nrtc ( ` H ~ ~ lO , CRT ' can partially activate the lnc promoter when its distance from the promoter is increased by 11 base-pairs , but not by five base-pairs , both in uiuo  and in r * itro ( St. raney et n / .