Figure 1
From: Structure-function analysis of the DNA-binding domain of a transmembrane transcriptional activator
Crystal structure of the CadC DNA-binding domain (DBD). (a) Scheme showing the transcriptional activation of cadBA genes by CadC in dependence of low pH and increased lysine concentration. The mechanism requires dimerization and therefore two DBDs are shown to bind the cadBA promoter (PcadBA). (b) Scheme showing the domain organization of CadC from E. coli. The DNA-binding domain is shown in blue. Numbers indicate amino acid positions. TM, transmembrane domain. (c) Cartoon representation of the E. coli CadC1-107 DBD from two views. Selected secondary structure elements are annotated. (d) Superposition of CadC1-107 (blue) as in (c) with the bacterial transcriptional activator PhoB in complex with DNA (magenta)16. Note that only one PhoB monomer and only part of the DNA are shown for clarity. Secondary structure elements involved in DNA-binding by CadC are annotated. The PhoB transactivation loop necessary for binding to RNA polymerase is indicated. Pictures were created with PyMol (Delano Scientific).
