title: The predatory bacterium Bdellovibrio bacteriovorus aspartyl-tRNA synthetase recognizes tRNAAsn as a substrate.
abstract: The predatory bacterium Bdellovibrio bacteriovorus preys on other Gram-negative bacteria and was predicted to be an asparagine auxotroph. However, despite encoding asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase, B. bacteriovorus also contains the amidotransferase GatCAB. Deinococcus radiodurans, and Thermus thermophilus also encode both of these aminoacyl-tRNA synthetases with GatCAB. Both also code for a second aspartyl-tRNA synthetase and use the additional aspartyl-tRNA synthetase with GatCAB to synthesize asparagine on tRNAAsn. Unlike those two bacteria, B. bacteriovorus encodes only one aspartyl-tRNA synthetase. Here we demonstrate the lone B. bacteriovorus aspartyl-tRNA synthetase catalyzes aspartyl-tRNAAsn formation that GatCAB can then amidate to asparaginyl-tRNAAsn. This non-discriminating aspartyl-tRNA synthetase with GatCAB thus provides B. bacteriovorus a second route for Asn-tRNAAsn formation with the asparagine synthesized in a tRNA-dependent manner. Thus, in contrast to a previous prediction, B. bacteriovorus codes for a biosynthetic route for asparagine. Analysis of bacterial genomes suggests a significant number of other bacteria may also code for both routes for Asn-tRNAAsn synthesis with only a limited number encoding a second aspartyl-tRNA synthetase.
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Ariel
authors.initials: A
authors.lastname: Alperstein
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Brittany
authors.initials: B
authors.lastname: Ulrich
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Garofalo
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Ruth
authors.initials: R
authors.lastname: Dreisbach
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Hannah
authors.initials: H
authors.lastname: Raff
authors.affiliation: Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America.
authors.forename: Kelly
authors.initials: K
authors.lastname: Sheppard
mesh_terms: D001226:Aspartate-tRNA Ligase / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D001501:Bdellovibrio / Q000201:enzymology*; D053898:Biosynthetic Pathways; D004926:Escherichia coli; D005816:Genetic Complementation Test; D007700:Kinetics; D012348:RNA, Transfer, Asn / Q000737:chemistry*; D013379:Substrate Specificity; D046249:Transfer RNA Aminoacylation
chemical_list: D001426:Bacterial Proteins; D012348:RNA, Transfer, Asn; D001226:Aspartate-tRNA Ligase