The Molecular Dynamics Simulation And Experimental Verification For The Autoinhibition Mechanisms Of ETS-1 Transcription Factor Regulated By Phosphorylation

Transcription factors(TFs)play direct roles in the transformation and transfer of cancer,and the regulation or inhibition of TFs has been the main means to treat cancer.ETS-1 TF regulates the transcription process by the ETS domain bind to DNA.The over-expressed ETS-1 TF is also a major player in the cancer development,thus this protein is identified as a target for the drug design.Many strategies have been used in the drug targeting research of ETS-1.Early attempts to target protein-DNA interactions to weaken the binding ability of the ETS domain and DNA,but it often takes years from the rational drug design to the clinical experiments.However,SRR could significantly inhibit the binding between the protein and DNA by phosphorylating,it is a more potent approach compared with the drug design.It is difficult for the experimental technologies to provide the complete structural information and the transient interaction of the proteins,molecular dynamics(MD)simulations is a complementary method with the experiments.In this research,we firstly employed the enhanced sampling molecular dynamics methods to study the phosphorylation mechanism of ETS-1 from the all-atom level,explore the interactions between SRR and ETS domain and the conformational change of the protein after phosphorylation.Then we combined with the experimental methods to explain the autoinhibition induced by the SRR phosphorylation.Our work provides an instructive reference for cancer research.The concrete results are as following:(1)After SRR phosphorylation,phosphoserine located in the alkaline region of H3 helix induced by the electrostatic interaction and formed the steric hindrance in space to inhibit the binding between the protein and DNA.(2)Phosphorylation enhanced the hydrophobic contact between the SRR and ETS domain and decrease the native hydrophobic interaction of H1-H3 led to the H3 unfold.(3)The mutation in the L337 A and W338 A led to the binding affinity of protein-DNA decreased,it confirmed that the integrality of the hydrophobic network is crucial for maintaining the stable structure of the protein.This paper was mainly divided into five chapters.In Chapter 1,we mainly introduce the structural characteristics and physiological function of IDRs,the structure,function and pathological significance of the ETS-1 and the research status of the ETS-1 autoinhibition and molecular dynamics simulation.Furthermore,the theory of MD simulation,enhanced sampling methods,analysis methods,and experimental methods are introduced.In Chapter 3,we investigate the structural characteristics of the isolated dephosphorylated and phosphorylated SRR,then we study the ?N279 and ?p N279 by BE-Meta D method.In Chapter 4,the allosteric mechanism is verified by the simulation of the ETS-1 mutants.In Chapter 5,we demonstrate the autoinhibition induced by the allosteric mechanism by experiments.In Chapter 6,the conclusions and prospects are presented.