Table 1.

Genes or operons in Escherichia coli known or predicted to be regulated with a DNA loop responsible for transcriptional repression^a

^aData under the column heads are as follows. TF, transcription factor forming or predicted to form the DNA loop. Configuration, configuration of the binding sites responsible for DNA loop formation: the black boxes show the positions of the repressor binding sites relative to the transcription start site, indicated by a bent arrow, and the total number of binding sites (bs) and the distance between the first and last sites are indicated. Other TF, includes other transcription factors (CRP, H-NS, IHF, Fis, or HU) binding in the regulatory region that could have an impact on DNA loop formation. ref, reference(s) to the literature that validate or suggest regulation involving a DNA loop mechanism for this operon or give evidence against looping. Boldface indicates those operons where the loop has been clearly demonstrated.