Structure, function, and tethering of DNA-binding domains in σ54 transcriptional activators

摘要: We compare the structure, activity, and linkage of DNA-binding domains (DBDs) from σ(54) transcriptional activators discuss how properties DBDs linker to neighboring domain are affected by overall requirements full proteins. These bind upstream specific promoters that utilize σ(54)-polymerase. Upon receiving a signal assemble into hexamers, which then, through adenosine triphosphate (ATP) hydrolysis, drive conformational change in polymerase enables transcription initiation. present structures nitrogen regulatory protein C 1 (NtrC1) Nif-like homolog 2 (Nlh2) thermophile Aquifex aeolicus. The these their relationship other parts discussed. compared with previously determined NtrC4, NtrC, ZraR, factor for inversion stimulation. N-terminal linkers connect central NtrC1 Nlh2 were studied found be unstructured. Additionally, crystal structure full-length was solved, but density extremely weak, further indicating between ATPase functions as flexible tether. Flexible linking is likely necessary allow assembly active hexameric ring. comparison this set also shows clearly strong dimerization DBD only occurs when do not dimerize strongly.