?
Transcriptional regulator AcaB This family of proteins is found in the IncC family of broad-host-range plasmids which enables the spread of antibiotic resistance genes among human enteric pathogens. Recently, AcaB member has been characterized as a transcriptional regulator that plays a crucial role in the regulation of IncC conjugation. It is a DNA binding protein which binds upstream of the acaDB promoter to increase its transcription and, in turn, acaDB activates the transcription of IncC conjugation genes. Structurally, AcaB consists of two helical hairpins in tandem which assemble into an anti-parallel four-helix bundle to form a two-stranded antiparallel beta-sheet positioned parallel to the helices. This is structurally similar to bacterial transcription factors from the ribbon-helix-helix (RHH) superfamily.
|