title: The Role of the Interdomain Interactions on RfaH Dynamics and Conformational Transformation.
abstract: The transcription antiterminator RfaH has been shown to undergo major structural rearrangements to perform multiple functions. Structural determination of the C-terminal domain (CTD) of RfaH showed that it can exist as either an α-helix bundle when interfacing with the N-terminal domain (NTD) or as a β-barrel conformation when it is not interfacing with the NTD. In this paper, we investigate the full RfaH with both CTD and NTD using a variety of all-atom molecular dynamics (MD) simulation techniques, including targeted molecular dynamics, steered molecular dynamics, and adaptive biasing force, and calculate potentials of mean force. We also use network analysis to determine communities of amino acids that are important in transferring information about structural changes. We find that the CTD-NTD interdomain interactions constitute the main barrier in the CTD α-helix to β-barrel structural conversion. Once the interfacial interactions are broken, the structural conversion of the CTD is relatively easy. We determined which amino acids play especially important roles in controlling the interdomain motions and also describe subtle structural changes that may be important in the functioning of RfaH.
authors.affiliation: Department of Physics, Florida International University , Miami, Florida 33199, United States.
authors.forename: Jeevan B
authors.initials: JB
authors.lastname: GC
authors.affiliation: Department of Physics, Florida International University , Miami, Florida 33199, United States.
authors.forename: Bernard S
authors.initials: BS
authors.lastname: Gerstman
authors.affiliation: Department of Physics, Florida International University , Miami, Florida 33199, United States.
authors.forename: Prem P
authors.initials: PP
authors.lastname: Chapagain
mesh_terms: D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010445:Peptide Elongation Factors / Q000737:chemistry*; D011487:Protein Conformation; D015534:Trans-Activators / Q000737:chemistry*
chemical_list: D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; C106401:RfaH protein, E coli; D015534:Trans-Activators