A glycine hinge for tRNA-dependent translocation of editing substrates to prevent errors by leucyl-tRNA synthetase.
Aminoacyl-tRNA synthetases often rely on a proofreading mechanism to clear mischarging errors before they can be incorporated into newly synthesized proteins. Leucyl-tRNA synthetase (LeuRS) houses a hydrolytic editing pocket in a domain that is distinct from its aminoacylation domain. Mischarged amino acids are transiently translocated approximately 30A between active sites for editing by an unknown tRNA-dependent mechanism. A glycine within a flexible beta-strand that links the aminoacylation and editing domains of LeuRS was determined to be important to tRNA translocation. The translocation-defective mutation also demonstrated that the editing site screens both correctly and incorrectly charged tRNAs prior to product release.
Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
Anjali P
AP
Mascarenhas
Susan A
SA
Martinis
D000595:Amino Acid Sequence; D049148:Aminoacylation; D020134:Catalytic Domain; D004926:Escherichia coli / Q000201:enzymology; D005998:Glycine; D007935:Leucine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D017434:Protein Structure, Tertiary; D012343:RNA, Transfer / Q000378:metabolism*
D012343:RNA, Transfer; D007935:Leucine-tRNA Ligase; D005998:Glycine