title: Multiple pathways promote dynamical coupling between catalytic domains in Escherichia coli prolyl-tRNA synthetase.
abstract: Aminoacyl-tRNA synthetases are multidomain enzymes that catalyze covalent attachment of amino acids to their cognate tRNA. Cross-talk between functional domains is a prerequisite for this process. In this study, we investigate the molecular mechanism of site-to-site communication in Escherichia coli prolyl-tRNA synthetase (Ec ProRS). Earlier studies have demonstrated that evolutionarily conserved and/or co-evolved residues that are engaged in correlated motion are critical for the propagation of functional conformational changes from one site to another in modular proteins. Here, molecular simulation and bioinformatics-based analysis were performed to identify dynamically coupled and evolutionarily constrained residues that form contiguous pathways of residue-residue interactions between the aminoacylation and editing domains of Ec ProRS. The results of this study suggest that multiple pathways exist between these two domains to maintain the dynamic coupling essential for enzyme function. Moreover, residues in these interaction networks are generally highly conserved. Site-directed changes of on-pathway residues have a significant impact on enzyme function and dynamics, suggesting that any perturbation along these pathways disrupts the native residue-residue interactions that are required for effective communication between the two functional domains. Free energy analysis revealed that communication between residues within a pathway and cross-talk between pathways are important for coordinating functions of different domains of Ec ProRS for efficient catalysis.
authors.affiliation: Department of Chemistry, University of Wisconsin-Eau Claire, Wisconsin 54702, United States.
authors.forename: James M
authors.initials: JM
authors.lastname: Johnson
authors.forename: Brianne L
authors.initials: BL
authors.lastname: Sanford
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Strom
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Tadayon
authors.forename: Brent P
authors.initials: BP
authors.lastname: Lehman
authors.forename: Arrianna M
authors.initials: AM
authors.lastname: Zirbes
authors.forename: Sudeep
authors.initials: S
authors.lastname: Bhattacharyya
authors.forename: Karin
authors.initials: K
authors.lastname: Musier-Forsyth
authors.forename: Sanchita
authors.initials: S
authors.lastname: Hati
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry* / Q000502:physiology; D020134:Catalytic Domain; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000502:physiology; D056004:Molecular Dynamics Simulation; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D029968:Escherichia coli Proteins; D000604:Amino Acyl-tRNA Synthetases; C100134:prolyl T RNA synthetase