title: tRNA recognition by glutamyl-tRNA reductase.
abstract: During the first step of porphyrin biosynthesis in Archaea, most bacteria, and in chloroplasts glutamyl-tRNA reductase (GluTR) catalyzes the NADPH-dependent reduction of glutamyl-tRNA to glutamate-1-semialdehyde. Elements in tRNA(Glu) important for utilization by Escherichia coli GluTR were determined by kinetic analysis of 51 variant transcripts of E. coli Glu-tRNA(Glu). Base U8, the U13*G22**A46 base triple, the tertiary Watson-Crick base pair 19*56, and the lack of residue 47 are required for GluTR recognition. All of these bases contribute to the formation of the unique tertiary core of E. coli tRNA-(Glu). Two tRNA(Glu) molecules lacking the entire anticodon stem/loop but retaining the tertiary core structure remained substrates for GluTR, while further decreasing tRNA size toward a minihelix abolished GluTR activity. RNA footprinting experiments revealed the physical interaction of GluTR with the tertiary core of Glu-tRNA(Glu). E. coli GluTR showed clear selectivity against mischarged Glu-tRNA(Gln). We concluded that the unique tertiary core structure of E. coli tRNA(Glu) was sufficient for E. coli GluTR to distinguish specifically its glutamyl-tRNA substrate.
authors.affiliation: Institut für Mikrobiologie, Technical University Braunschweig, Spielmannstrasse 7, P. O. Box 3329, D-38023 Braunschweig, Germany.
authors.forename: Lennart
authors.initials: L
authors.lastname: Randau
authors.forename: Stefan
authors.initials: S
authors.lastname: Schauer
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ambrogelly
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Salazar
authors.forename: Jürgen
authors.initials: J
authors.lastname: Moser
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Sekine
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Dieter
authors.initials: D
authors.lastname: Söll
authors.forename: Dieter
authors.initials: D
authors.lastname: Jahn
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004926:Escherichia coli / Q000378:metabolism; D014644:Genetic Variation; D005822:Genetic Vectors; D007700:Kinetics; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D012352:RNA, Transfer, Glu / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013053:Spectrophotometry; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D012333:RNA, Messenger; D012352:RNA, Transfer, Glu; D011994:Recombinant Proteins; D012343:RNA, Transfer; D000445:Aldehyde Oxidoreductases; C067282:glutamyl tRNA reductase