scholarly journals Characterization of Two Seryl-tRNA Synthetases in Albomycin-Producing Streptomyces sp. Strain ATCC 700974

2009 ◽  
Vol 53 (11) ◽  
pp. 4619-4627 ◽  
Author(s):  
Yu Zeng ◽  
Hervé Roy ◽  
Preeti B. Patil ◽  
Michael Ibba ◽  
Shawn Chen

ABSTRACTThe Trojan horse antibiotic albomycin, produced byStreptomycessp. strain ATCC 700974, contains a thioribosyl nucleoside moiety linked to a hydroxamate siderophore through a serine residue. The seryl nucleoside structure (SB-217452) is a potent inhibitor of seryl-tRNA synthetase (SerRS) in the pathogenic bacteriumStaphylococcus aureus, with a 50% inhibitory concentration (IC50) of ∼8 nM. In the albomycin-producingStreptomycessp., a bacterial SerRS homolog (Alb10) was found to be encoded in a biosynthetic gene cluster in addition to anotherserRSgene (serS1) at a different genetic locus. Alb10, named SerRS2 herein, is significantly divergent from SerRS1, which shows high homology to the housekeeping SerRS found in otherStreptomycesspecies. We genetically and biochemically characterized the two genes and the proteins encoded. Both genes were able to complement a temperature-sensitiveserSmutant ofEscherichia coliand allowed growth at a nonpermissive temperature.serS2was shown to confer albomycin resistance, with specific amino acid residues in the motif 2 signature sequences of SerRS2 playing key roles. SerRS1 and SerRS2 are comparably efficient in vitro, but theKmof serine for SerRS2 measured during tRNA aminoacylation is more than 20-fold higher than that for SerRS1. SB-217452 was also enzymatically generated and purified by two-step chromatography. Its IC50against SerRS1 was estimated to be 10-fold lower than that against SerRS2. In contrast, both SerRSs displayed comparable inhibition kinetics for serine hydroxamate, indicating that SerRS2 was specifically resistant to SB-217452. These data suggest that miningStreptomycesgenomes for duplicated aminoacyl-tRNA synthetase genes could provide a novel approach for the identification of natural products targeting aminoacyl-tRNA synthetases.

1982 ◽  
Vol 152 (1) ◽  
pp. 357-362
Author(s):  
D Elseviers ◽  
P Gallagher ◽  
A Hoffman ◽  
B Weinberg ◽  
I Schwartz

A 22-kilobase fragment of the Escherichia coli chromosome which contains the genes for translation initiation factor 3, phenylalanyl-tRNA synthetase, and threonyl-tRNA synthetase was cloned into plasmid pACYC184. The hybrid plasmid (designated pID1) complements a temperature-sensitive pheS lesion in E. coli NP37. pID1-transformed NP37 overproduce initiation factor 3 and phenylalanyl-tRNA synthetase. Gene expression from pID1 was studied in vitro in a coupled transcription-translation system and in minicells. The results suggest that the genes for initiation factor 3 and phenylalanyl- and threonyl-tRNA synthetase are regulated by different mechanisms.


2019 ◽  
Vol 35 (6) ◽  
pp. 39-50
Author(s):  
T.V. Yuzbashev ◽  
A.S. Fedorov ◽  
F.V. Bondarenko ◽  
A.S. Savchenko ◽  
T.V. Vybornaya ◽  
...  

The present work describes an approach that improves the properties of the strain producing L-threonine via the reduction in the biomass accumulation during fermentation. Glutamyl- and glutaminyl-tRNA synthetases were chosen as targets. Mutants carrying temperature-sensitive alleles were obtained. It was shown that the used system caused the suppression of the function of tRNA synthetases which led to a rapid arrest of the culture growth, and an increase in productivity and yield of the L-threonine synthesis. One of the temperature-sensitive strains was used to obtain under non-permissive conditions of mutants with the suppressed above phenotype. Some of these mutants accumulate less biomass and produce by 10-12% more threonine than the original strain. Escherichia coli, producing strain, threonine, aminoacyl-tRNA synthetase, ts-mutation This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project code RFMEFI61017X0011), and it was carried out using the equipment of the National Bio-Resource Center All-Russian Collection of Industrial Microorganisms, NRC «Kurchatov Institute» - GosNIIgenetika.


1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez

In contrast with most aminoacyl-tRNA synthetases, the lysyl-tRNA synthetase of Escherichia coli is coded for by two genes, the normal lysS gene and the inducible lysU gene. During its purification from E. coli K12, lysyl-tRNA synthetase was monitored by its aminoacylation and adenosine(5′)tetraphospho(5′)adenosine (Ap4A) synthesis activities. Ap4A synthesis was measured by a new assay using DEAE-cellulose filters. The heterogeneity of lysyl-tRNA synthetase (LysRS) was revealed on hydroxyapatite; we focused on the first peak, LysRS1, because of its higher Ap4A/lysyl-tRNA activity ratio at that stage. Additional differences between LysRS1 and LysRS2 (major peak on hydroxyapatite) were collected. LysRS1 was eluted from phosphocellulose in the presence of the substrates, whereas LysRS2 was not. Phosphocellulose chromatography was used to show the increase of LysRS1 in cells submitted to heat shock. Also, the Mg2+ optimum in the Ap4A-synthesis reaction is much higher for LysRS1. LysRS1 showed a higher thermostability, which was specifically enhanced by Zn2+. These results in vivo and in vitro strongly suggest that LysRS1 is the heat-inducible lysU-gene product.


Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 473 ◽  
Author(s):  
Takuya Umehara ◽  
Saori Kosono ◽  
Dieter Söll ◽  
Koji Tamura

Protein lysine acetylation is a widely conserved posttranslational modification in all three domains of life. Lysine acetylation frequently occurs in aminoacyl-tRNA synthetases (aaRSs) from many organisms. In this study, we determined the impact of the naturally occurring acetylation at lysine-73 (K73) in Escherichia coli class II alanyl-tRNA synthetase (AlaRS) on its alanylation activity. We prepared an AlaRS K73Ac variant in which Nε-acetyl-l-lysine was incorporated at position 73 using an expanded genetic code system in E. coli. The AlaRS K73Ac variant showed low activity compared to the AlaRS wild type (WT). Nicotinamide treatment or CobB-deletion in an E. coli led to elevated acetylation levels of AlaRS K73Ac and strongly reduced alanylation activities. We assumed that alanylation by AlaRS is affected by K73 acetylation, and the modification is sensitive to CobB deacetylase in vivo. We also showed that E. coli expresses two CobB isoforms (CobB-L and CobB-S) in vivo. CobB-S displayed the deacetylase activity of the AlaRS K73Ac variant in vitro. Our results imply a potential regulatory role for lysine acetylation in controlling the activity of aaRSs and protein synthesis.


2012 ◽  
Vol 90 (6) ◽  
pp. 731-749 ◽  
Author(s):  
Manoja B.K. Eswara ◽  
Ashley Clayton ◽  
Dev Mangroo

Utp8p is an essential nucleolar protein that channels aminoacyl-tRNAs from aminoacyl-tRNA synthetases in the nucleolus to the nuclear tRNA export receptors located in the nucleoplasm and nuclear pore complex in Saccharomyces cerevisiae . Utp8p is also part of the U3 snoRNA-associated protein complex involved in 18S rRNA biogenesis in the nucleolus. We report that Utp22p, which is another member of the U3 snoRNA-associated protein complex, is also an intranuclear component of the nuclear tRNA export machinery. Depletion of Utp22p results in nuclear retention of mature tRNAs derived from intron-containing and intronless precursors. Moreover, Utp22p copurifies with the nuclear tRNA export receptor Los1p, the aminoacyl-tRNA synthetase Tys1p and Utp8p, but not with the RanGTPase Gsp1p and the nuclear tRNA export receptor Msn5p. Utp22p interacts directly with Utp8p and Los1p in a tRNA-independent manner in vitro. Utp22p also interacts directly with Tys1p, but this binding is stimulated when Tys1p is bound to tRNA. However, Utp22p, unlike Utp8p, does not bind tRNA saturably. These data suggest that Utp22p recruits Utp8p to aminoacyl-tRNA synthetases in the nucleolus to collect aminoacyl-tRNA and then accompanies the Utp8p–tRNA complex to deliver the aminoacyl-tRNAs to Los1p but not Msn5p. It is possible that Nrap/Nol6, the mammalian orthologue of Utp22p, plays a role in channelling aminoacyl-tRNA to the nuclear tRNA export receptor exportin-t.


2021 ◽  
Author(s):  
Jaryd R Sullivan ◽  
Andreanne Lupien ◽  
Elias Kalthoff ◽  
Claire Hamela ◽  
Lorne Taylor ◽  
...  

Certain aminoacyl-tRNA synthetases developed a proofreading mechanism to ensure aminoacylation of tRNAs with cognate amino acids. Epetraborole (EPT) was identified as an inhibitor of the leucyl-tRNA synthetase (LeuRS) editing site in Mycobacterium abscessus. EPT displayed enhanced activity against M. abscessus over Mycobacterium tuberculosis. Crystallographic and equilibrium binding data showed that EPT binds LeuRSMabs and LeuRSMtb with similar Kd. Proteomic analysis revealed that when M. abscessus LeuRS mutants were fed the non-proteinogenic amino acid norvaline, leucine residues in proteins were replaced by norvaline, inducing expression of GroEL chaperonins and Clp proteases. In vitro data revealed that supplementation of media with norvaline reduced the emergence of EPT mutants in both M. abscessus and M. tuberculosis. The combination of EPT and norvaline had improved in vivo efficacy compared to EPT in a murine model of M. abscessus infection.


Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 672 ◽  
Author(s):  
Eunji Kim ◽  
Yern-Hyerk Shin ◽  
Tae Ho Kim ◽  
Woong Sub Byun ◽  
Jinsheng Cui ◽  
...  

The cyclic depsipeptides ohmyungsamycin (OMS) A (1) and B (2), isolated from the marine-derived Streptomyces sp. SNJ042, contain two non-proteinogenic amino acid residues, β-hydroxy-l-phenylalanine (β-hydroxy-l-Phe) and 4-methoxy-l-tryptophan (4-methoxy-l-Trp). Draft genome sequencing of Streptomyces sp. SNJ042 revealed the OMS biosynthetic gene cluster consisting of a nonribosomal peptide synthetase (NRPS) gene and three genes for amino acid modification. By gene inactivation and analysis of the accumulated products, we found that OhmL, encoding a P450 gene, is an l-Phe β-hydroxylase. Furthermore, OhmK, encoding a Trp 2,3-dioxygenase homolog, and OhmJ, encoding an O-methyltransferase, are suggested to be involved in hydroxylation and O-methylation reactions, respectively, in the biosynthesis of 4-methoxy-l-Trp. In addition, the antiproliferative and antituberculosis activities of the OMS derivatives dehydroxy-OMS A (4) and demethoxy-OMS A (6) obtained from the mutant strains were evaluated in vitro. Interestingly, dehydroxy-OMS A (4) displayed significantly improved antituberculosis activity and decreased cytotoxicity compared to wild-type OMS A.


1978 ◽  
Vol 176 (1) ◽  
pp. 305-318 ◽  
Author(s):  
Julia Hughes ◽  
Graham Mellows

The mode of action of the antibiotic pseudomonic acid has been studied in Escherichia coli. Pseudomonic acid strongly inhibits protein and RNA synthesis in vivo. The antibiotic had no effect on highly purified DNA-dependent RNA polymerase and showed only a weak inhibitory effect on a poly(U)-directed polyphenylalanine-forming ribosomal preparation. Chloramphenicol reversed inhibition of RNA synthesis in vivo. Pseudomonic acid had little effect on RNA synthesis in a regulatory mutant, E. coli B AS19 RCrel, whereas protein synthesis was strongly inhibited. In pseudomonic acid-treated cells, increased concentrations of ppGpp, pppGpp and ATP were observed, but the GTP pool size decreased, suggesting that inhibition of RNA synthesis is a consequence of the stringent control mechanism imposed by pseudomonic acid-induced deprivation of an amino acid. Of the 20 common amino acids, only isoleucine reversed the inhibitory effect in vivo. The antibiotic was found to be a powerful inhibitor of isoleucyl-tRNA synthetase both in vivo and in vitro. Of seven other tRNA synthetases assayed, only a weak inhibitory effect on phenylalanyl-tRNA synthetase was observed; this presumably accounted for the weak effect on polyphenylalanine formation in a ribosomal preparation. Pseudomonic acid also significantly de-repressed threonine deaminase and transaminase B activity, but not dihydroxyacid dehydratase (isoleucine-biosynthetic enzymes) by decreasing the supply of aminoacylated tRNAIle. Pseudomonic acid is the second naturally occurring inhibitor of bacterial isoleucyl-tRNA synthetase to be discovered, furanomycin being the first.


2010 ◽  
Vol 430 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Xiao-Long Zhou ◽  
Min Tan ◽  
Meng Wang ◽  
Xin Chen ◽  
En-Duo Wang

Some aaRSs (aminoacyl-tRNA synthetases) develop editing mechanisms to correct mis-charged tRNA. The CP1 (connective peptide 1) domain of LeuRS (leucyl-tRNA synthetase) contains the editing active site, which is the proven target for the broad-spectrum drug AN2690 (5-fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole). The ESI (eukarya-specific insertion 1) in the CP1 domain of GlLeuRS (Giardia lamblia LeuRS) has been identified. Similar substitution with the ESI from HsLeuRS (Homo sapiens LeuRS) impeded the leucine activation, aminoacylation and post-transfer editing of the enzyme, but had no effect on the editing specificity toward non-specific amino acids. Thr341 in GlLeuRS served as a specificity discriminator, as found in other LeuRS systems, although its substitution with an alanine residue did not destroy Leu-tRNALeu synthesis in vitro and in vivo. The Arg338 was crucial for tRNALeu charging and the Asp440 was crucial for leucine activation and aminoacylation. The post-transfer editing required the CTD (C-terminal domain), Arg338 and Asp440 of GlLeuRS. Interestingly, GlLeuRS was completely resistant to the AN2690, which is an inhibitor of various LeuRSs. The universally conserved aspartate residue in the LeuRS CP1 domains was responsible for the resistance of GlLeuRS and another recently reported AN2690-resistant AaLeuRS (Aquifex aeolicus LeuRS). Our results indicate the functional divergence of some absolutely conserved sites, improve the understanding of the editing function of eukaryotic/archaeal LeuRSs and shed light on the development of a GlLeuRS-specific inhibitor for the treatment of giardiasis.


2020 ◽  
Vol 8 (9) ◽  
pp. 1390 ◽  
Author(s):  
Sunghoon Hwang ◽  
Ly Thi Huong Luu Le ◽  
Shin-Il Jo ◽  
Jongheon Shin ◽  
Min Jae Lee ◽  
...  

Pentaminomycins C–E (1–3) were isolated from the culture of the Streptomyces sp. GG23 strain from the guts of the mealworm beetle, Tenebrio molitor. The structures of the pentaminomycins were determined to be cyclic pentapeptides containing a modified amino acid, N5-hydroxyarginine, based on 1D and 2D NMR and mass spectroscopic analyses. The absolute configurations of the amino acid residues were assigned using Marfey’s method and bioinformatics analysis of their nonribosomal peptide biosynthetic gene cluster (BGC). Detailed analysis of the BGC enabled us to propose that the structural variations in 1–3 originate from the low specificity of the adenylation domain in the nonribosomal peptide synthetase (NRPS) module 1, and indicate that macrocyclization can be catalyzed noncanonically by penicillin binding protein (PBP)-type TE. Furthermore, pentaminomycins C and D (1 and 2) showed significant autophagy-inducing activities and were cytoprotective against oxidative stress in vitro.


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