RT Journal Article SR Electronic(1) A1 Stauffer, Lorraine T. A1 Stauffer, George V.YR 1998 T1 Roles for GcvA-binding sites 3 and 2 and the Lrp-binding region in gcvT:: lacZ expression in Escherichia coli JF Microbiology, VO 144 IS 10 SP 2865 OP 2872 DO https://doi.org/10.1099/00221287-144-10-2865 PB Microbiology Society, SN 1465-2080, AB SUMMARY: GcvA and Lrp are both necessary for activation of the gcv operon. The upstream GcvA-binding sites 3 and 2 were separated from the Lrplbinding region and the rest of the gcv control region. Moving these sites by 1 or 2 helical turns of DNA further from the gcv promoter reduces, but does not eliminate, either GcvA-mediated activation or repression of a gcvT:: lac2 gene fusion. However, moving these sites by 1-5 or 2.5 helical turns of DNA results inm a GcvA-mediated super-repression of the operon. This repression is dependent on Lrp and is partially dependent on GcvR. Lrp bound to the gcv control region induces a bend in the DNA. Based on these results, a model for gcw regulation is presented in which Lrp plays a primarily structural role, by bending the DNA and GcvA functions as the activator protein., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-144-10-2865