Fig. 2.

EMSAs with ArgP and the full-length cis regulatory region of lysP (A) or one of its two deletion derivatives (B, C) in the absence (Nil) or presence (Lys) of the coeffector Lys. The extent in base pairs of the lysP regulatory region used in each experiment is given in parentheses. ArgP monomer concentrations are indicated for each lane. Bands corresponding to free DNA and to DNA in binary complex with ArgP (the latter is not observed in panel C) are marked by filled and open arrowheads, respectively. Lanes 12 to 14 of panel A depict the results of the addition of a 100-fold excess of unlabeled competitor DNA, either specific, that is the full-length lysP fragment (S), or one of two different nonspecific DNA fragments (NS1 and NS2), to the mixtures for EMSA reactions undertaken with 160 nM ArgP. NS1 is a 253-bp fragment from the ilvG locus obtained by PCR with the primers 5′-CAGCAACACTGCGCGCAGCTGCGTGATG-3′ and 5′-CTTGTGCGCCAACCGCCGCCGGTAAAC-3′ (genomic coordinates 3949570 to 3949822 [40]), while NS2 is the same 295-bp lacZ fragment that was used for the EMSA whose results are shown in Fig. 3.