The C-Domain of the NAC Transcription Factor ANAC019 Is Necessary for pH-Tuned DNA Binding through a Histidine Switch in the N-Domain
2018
Mooseok Kang | Sangyeol Kim | Hyo Jung Kim | Pravesh Shrestha | Ji-hye Yun | Bong-Kwan Phee | Weontae Lee | Hong Gil Nam | Iksoo Chang
Summary: 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. Keywords: transcription factor, pH-tuned DNA-binding affinity, histidine switch, intrinsically disordered region, electric dipole moment
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