The StpA protein functions as a molecular adapter to mediate repression of the bgl operon by truncated H-NS in Escherichia coli.

The mechanism of repression of the beta-glucoside utilization (bgl) operon of Escherichia coli by a carboxy-terminally truncated derivative of the nucleoid-associated protein H-NS which is defective in DNA binding was investigated. The DNA-binding function of the H-NS-like protein StpA was found to be necessary for repression, which is consistent with a role for StpA as a DNA-binding adapter for mutant derivatives of H-NS.