Steiert J G, Kubu C, Stauffer G V
Department of Microbiology, University of Iowa, Iowa City 52242.
FEMS Microbiol Lett. 1992 Dec 1;78(2-3):299-304. doi: 10.1016/0378-1097(92)90044-o.
Site-directed mutagenesis was used to change the PurR binding site in the control region of a glyA-lac gene fusion. Mutations that changed the PurR binding sequence away from the consensus sequence reduced PurR binding, which correlated with reduced purine-mediated repression. Mutations that changed the binding sequence toward the consensus sequence had no significant effect on either PurR binding or purine-mediated repression. Hypoxanthine and guanine, co-repressors for PurR-mediated regulation of the pur regulon, increased binding of PurR to glyA operator DNA.
定点诱变用于改变glyA-lac基因融合体控制区域中的PurR结合位点。使PurR结合序列偏离共有序列的突变会降低PurR结合，这与嘌呤介导的阻遏作用减弱相关。使结合序列趋向共有序列的突变对PurR结合或嘌呤介导的阻遏作用均无显著影响。次黄嘌呤和鸟嘌呤是PurR介导的嘌呤操纵子调控的共阻遏物，它们增加了PurR与glyA操纵基因DNA的结合。
