possibly the yeast mitochondria have evolved to tolerate lower levels of fidelity in protein synthesis or have developed alternate mechanisms to enhance discrimination of leucine from non-cognate amino acids that can be misactivated by leucyl-tRNA synthetase
a two step reaction, the first of which is reversible, aminoacylation and editing by LeuRS require migration of the tRNA acceptor stem end between the canonical aminoacylation core and a separate domain called CP1 that is responsible for amino acid editing, post-transfer editing mechanism., overview
LeuRS has a hydrolytic active site that resides in a discrete amino acid editing domain called CP1, LeuRS misactivates many non-leucine amino acids, including isoleucine, valine, methionine, and also structurally similar metabolic cellular intermediate, but the enzyme has an editing active site that is competent for post-transfer editing of mischarged tRNA
the LeuRS CP1 domain can also support group I intron RNA splicing in the yeast mitochondria, overview, the RDW peptide, a highly conserved peptide within an RDW-containing motif, is important for enzyme interactions, the RDW peptide is dynamic and forms unique sets of interactions with the aminoacylation and editing complexes, overview
possibly the yeast mitochondria have evolved to tolerate lower levels of fidelity in protein synthesis or have developed alternate mechanisms to enhance discrimination of leucine from non-cognate amino acids that can be misactivated by leucyl-tRNA synthetase
leucyl-tRNA synthetase is an essential RNA splicing factor for yeast mitochondrial introns. RNA deletion mutants of the large bI4 intron are active in RNA splicing and the activity of the minimized bI4 intron is enhanced in vitro by the presence of the bI4 maturase or LeuRS
primary and tertiary structure, overview, the RDW peptide, a highly conserved peptide within an RDW-containing motif, is important for enzyme interactions, overview
primary and tertiary structures of the LeuRS unique C-terminal domain, overview, the C-terminal extension of about 60 amino acids forms a discrete domain, which is unique among the LeuRSs and interacts with the corner of the L-shaped tRNALeu, overview
mutant is significantly resistant to inhibitor AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Growth rate is moderately inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is significantly resistant to inhibitor AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Mutant D419A shows mischarging capacity with Ile. Growth rate is severly inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is significantly resistant to inhibitor AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Growth rate is moderately inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is significantly resistant to inhibitor AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Growth rate is moderately inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is significantly resistant to inhibitor AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Mutant T319A shows mischarging capacity with Ile. Growth rate is severly inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is inhibited by AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Growth rate is moderately inhibited in medium containing a large excess of norvaline and reduced leucine
mutant is inhibited by AN-2690. Mutant aminoacylation of yctRNALeu is not different from wild-type ycLeuRS. Growth rate is similar to wild-type. Growth rate is moderately inhibited in medium containing a large excess of norvaline and reduced leucine
site-directed mutagenesis, the mutant shows reduced activity and abolished editing activity and misaminoacylated isoleucine to tRNALeu compared to the wild-type enzyme
mutation of the highly conserved Asp residue, located in the CP1 domain, is responsible for editing mechanism, slightly reduced activity with L-leucine, mutant mischarges tRNALeu with isoleucine
deletion of the C-terminal domain peptide linker stimulates aminoacylation and editing activity shows that as the length of the peptide linker decreases, aminoacylation activity decreases. Mutant retains significant deacylation activity against mischarged Ile-tRNALeu
site-directed mutagenesis, mutation within the RDW peptide, no complementation of the null mutant strain QBY320, 30fold reduced activity compared to the wild-type enzyme
site-directed mutagenesis, mutation within the RDW peptide, complementation of the null mutant strain QBY320, 11fold reduced activity compared to the wild-type enzyme
site-directed mutagenesis, mutation within the RDW peptide, weak complementation of the null mutant strain QBY320, 30fold reduced activity compared to the wild-type enzyme
deletion of the leuS gene is lethal. Human cytoplasmic LeuRS can rescue the knock-out strain but not Escherichia coli LeuRS. LeuRS mutant strains T319, D419A, K404Y, S416D, D418R, T347A or T410A are also able to rescue the null mutant
deletion of the leuS gene is lethal. Human cytoplasmic LeuRS can rescue the knock-out strain but not Escherichia coli LeuRS. LeuRS mutant strains T319, D419A, K404Y, S416D, D418R, T347A or T410A are also able to rescue the null mutant
deletions of the C terminus differentially impact the two functions of the enzyme in splicing and aminoacylation in vivo, overview, a five-amino acid C-terminal deletion of LeuRS, which does not complement a null strain, can form a ternary complex with the bI4 intron and its maturase splicing partner, however, the complex fails to stimulate splicing activity, deletion of the entire yeast mitochondrial LeuRS C-terminal domain enhances its aminoacylation and amino acid editing activities
a series of deletions and chimeric variations in the peptide linker of the yeast mitochondrial LeuRS chimeric mutant that is fused to the Escherichia coli LeuRS C-terminal domain extension are created: a four residue deletion mutant of the yeast mitochondrial LeuRS chimera (Ym EcCTD Delta4) stimulates aminoacylation activity significantly compared to that of the chimera enzyme with no deletion within the linker peptide
an eight residue peptide linker deletion mutant that contains three (Ym EcCTD DELTA8/+3), six (Ym EcCTD DELTA8/+6), or nine (Ym EcCTD DELTA8/+9) residues from the Escherichia coli LeuRS linker peptide restors protein stability and activity. Within these three chimeric peptide linker swaps, successive increases in the length of the Escherichia coli chimeric peptide linker decreases aminoacylation activity progressively
expression of His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3), complementation abilities of wild-type and mutant enzymes of yeast null strain HM402 and Escherichia coli strain KL321, overview
Lincecum, T.L., Jr.; Tukalo, M.; Yaremchuk, A.; Mursinna, R.S.; Williams, A.M.; Sproat, B.S.; Van Den Eynde, W.; Link, A.; Van Calenbergh, S.; Grotli, M.; Martinis, S.A.; Cusack, S.
Structural and mechanistic basis of pre- and posttransfer editing by leucyl-tRNA synthetase