FIG. 4.
Overexpression and purification of GntR and CRP, demonstrated by SDS-PAGE of the purified His-tagged proteins. Lanes A and F, molecular weight standards; lanes B and E, cell extracts of strains M15(pNP-41) and M15(pNP-52) after IPTG induction; lanes C and D, purified GntR and CRP, respectively.