The affinity of transcription factors (TFs) for their target DNA is a critical determinant of gene expression. Whether the DNA-binding domain (DBD) of TFs alone can regulate binding affinity to DNA is an important question for identifying the design principle of TFs. We studied ANAC019, a member of the NAC TF family of proteins in Arabidopsis, and found a well-conserved histidine switch located in its DBD, which regulates both homodimerization and transcriptional control of the TF through H135 protonation. We found that the removal of a C-terminal intrinsically disordered region (IDR) in the TF abolished the pH-dependent binding of the N-terminal DBD to DNA. We propose a mechanism in which long-range electrostatic interactions between DNA and the negatively charged C-terminal IDR turns on the pH dependency of the DNA-binding affinity of the N-terminal DBD. Kang et al. find a histidine switch in the DNA-binding N-domain of the transcription factor ANAC019 that regulates both pH-dependent homodimerization and DNA binding. They propose that long-range electrostatic interactions between DNA and the negatively charged C-terminal turns on the pH dependency of the DNA-binding affinity of the N-terminal DNA-binding domain.
Bibliographical noteFunding Information:
This work was funded by the Creative Research Initiatives of the National Research Foundation (NRF) of Korea ( 2008-0061984 to M.K., S.K., and I.C.) and the DGIST Core Protein Resources Center ( N0001822 to I.C.). H.J.K., B.-K.P., and H.G.N. were supported by the Institute for Basic Science ( IBS-R013-D1 ). J.-h.Y., P.S., and W.L. were supported by Mid-career Researcher Program ( 2017R1A2B2008483 to W.L.) and Basic Science Research Program ( 2016R1A6A3A04010213 to J.-h.Y.) of NRF . We acknowledge the DGIST Supercomputing and Big Data Center for the dedicated allocation of supercomputing time.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)