Architecture of <i>Pseudomonas aeruginosa</i> glutamyl-tRNA synthetase defines a subfamily of dimeric class Ib aminoacyl-tRNA synthetases
Abstract
The aminoacyl-tRNA synthetases (AaRSs) are an ancient family of structurally diverse enzymes that are divided into two major classes. The functionalities of most AaRSs are inextricably linked to their oligomeric states. While GluRSs were previously classified as monomers, the current investigation reveals that the form expressed in Pseudomonas aeruginosa is a rotationally pseudosymmetrical homodimer featuring intersubunit tRNA binding sites. Both subunits display a highly bent, “pipe strap” conformation, with the anticodon binding domain directed toward the active site. The tRNA binding sites are similar in shape to those of the monomeric GluRSs, but are formed through an approximately 180-degree rotation of the anticodon binding domains and dimerization via the anticodon and D-arm binding domains. As a result, each anticodon binding domain is poised to recognize the anticodon loop of a tRNA bound to the adjacent protomer. Additionally, the anticodon binding domain has an α-helical C -terminal extension containing a conserved lysine-rich consensus motif positioned near the predicted location of the acceptor arm, suggesting dual functions in tRNA recognition. The unique architecture of Pa GluRS broadens the structural diversity of the GluRS family, and member synthetases of all bacterial AaRS subclasses have now been identified that exhibit oligomerization.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (21)
Michael K. Fenwick
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Stephen J. Mayclin
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Steve Seibold
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Amy E. DeRocher
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Sandhya Subramanian
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Isabelle Q. Phan
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
David M. Dranow
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Donald D. Lorimer
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Ariel B. Abramov
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Ryan Choi
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Stephen Nakazawa Hewitt
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Thomas E. Edwards
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
James M. Bullard
Chemistry Department, The University of Texas-Pan American
Kevin P. Battaile
New York Structural Biology Center
Iwona K. Wower
Department of Animal Sciences, Auburn University
Aimee C. Soe
Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory
Susan E. Tsutakawa
Scott Lovell
Department of Pathology
Peter J. Myler
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute
Jacek Wower
Bart L. Staker
Seattle Structural Genomics Center for Infectious Disease, Seattle Children’s Research Institute