Friday, October 30, 2015
4:00 pm, MRB 202
Dr. Iksoo Chang
Center for Proteome Biophysics, Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology
Negatively charged C-domain governs pH-tuned DNA binding of NAC transcription factor
Transcriptional control by transcription factors(Tfs) is a fundamental cellular regulatory mechanism. One of the key molecular mechanisms of transcriptional control is regulation of binding affinity of TFs to their target sequence responding to the intra- and extra-environmental conditions. NAC is a key plant transcription factor family. In Arabidopsis, 108 NAC TFs controls various aspects of plant development and environmental responses. They are composed of a highly conserved N-terminal DNA binding domain(DBD) and divergent C-terminal intrinsically disorderd region. A histidine in N-terminal DBD among 80% of the NAC members is conserved, implicating its possible importance. We asked the role of this conserved histidine for regulating DNA binding affinity of NAC19 TFs to their target sequences in response to the cellular pH through molecular dynamics simulations together with the in-vitro and in-vivo experimental study of NAC19 transcription factor. We demonstrate a mechanism that negatively charged C-domain of a dimeric NAC19 transcription factor are indispensable for conferring the pH-tuned DNA binding of the N-terminal DBD while a single histidine residue located in the NAC19 DBD execute regulatory function enroute to both NAC19 dimerizationand DNA binding.