GENES FOR TWO E. COLI AMINOACYL tRNA SYNTHETASES

1982 ◽  
pp. 49-56
Author(s):  
PAUL SCHIMMEL ◽  
TERESA KENG ◽  
SCOTT PUTNEY
Keyword(s):  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

scholarly journals Lysyl-tRNA synthetase from Escherichia coli K12. Chromatographic heterogeneity and the lysU-gene product

1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Activity Ratio ◽  
Deae Cellulose ◽  
Trna Synthetase ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

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.

scholarly journals Measuring the tolerance of the genetic code to altered codon size

2021 ◽  
Author(s):  
E. DeBenedictis ◽  
D. Söll ◽  
K. Esvelt
Keyword(s):  
Genetic Code ◽  
Protein Translation ◽  
Single Amino Acid ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases ◽  
Triplet Codon ◽  
Orthogonal Set ◽  
Expanded Genetic Code ◽  
Primordial Earth

SummaryProtein translation using four-base codons occurs in both natural and synthetic systems. What constraints contributed to the universal adoption of a triplet-codon, rather than quadruplet-codon, genetic code? Here, we investigate the tolerance of the E. coli genetic code to tRNA mutations that increase codon size. We found that tRNAs from all twenty canonical isoacceptor classes can be converted to functional quadruplet tRNAs (qtRNAs), many of which selectively incorporate a single amino acid in response to a specified four-base codon. However, efficient quadruplet codon translation often requires multiple tRNA mutations, potentially constraining evolution. Moreover, while tRNAs were largely amenable to quadruplet conversion, only nine of the twenty aminoacyl tRNA synthetases tolerate quadruplet anticodons. These constitute a functional and mutually orthogonal set, but one that sharply limits the chemical alphabet available to a nascent all-quadruplet code. Our results illuminate factors that led to selection and maintenance of triplet codons in primordial Earth and provide a blueprint for synthetic biologists to deliberately engineer an all-quadruplet expanded genetic code.

The Role of anticodon bases and the discriminator nucleotide in the recognition of some E. coli tRNAs by their aminoacyl-tRNA synthetases

1992 ◽  
Vol 35 (5) ◽  
Author(s):  
Mikio Shimizu ◽  
Haruichi Asahara ◽  
Koji Tamura ◽  
Tsunemi Hasegawa ◽  
Hyouta Himeno
Keyword(s):  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

Evolutionary relationship between Halobacterium cutirubrum and eukaryotes determined by use of aminoacyl-tRNA synthetases as phylogenetic probes

1980 ◽  
Vol 58 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Yau Kwok ◽  
J. Tze-Fei Wong
Keyword(s):  
Wheat Germ ◽  
Bacillus Stearothermophilus ◽  
Micrococcus Luteus ◽  
Myxococcus Xanthus ◽  
Evolutionary Relationship ◽  
Thermus Aquaticus ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases ◽  
Rhodopseudomonas Spheroides

The cross-species reactivities between tRNAs and aminoacyl-tRNA synthetases have been employed as a basis to estimate the relatedness of various prokaryotes to the eukaryotes. The tRNA of Halobacterium cutirubrum, unlike that of other prokaryotes tested, including Agrobacterium tumefaciens, Arthrobacter luteus, Bacillus subtilis, Bacillus stearothermophilus, Escherichia coli, Micrococcus luteus, Myxococcus xanthus, Rhodopseudomonas spheroides, and Thermus aquaticus, was found to share with yeast, rat liver, and wheat germ tRNA a distinct preference for aminoacylation by eukaryotic synthetases from yeast as opposed to prokaryotic synthetases from either E. coli or R. spheroides. These results suggest that phylogenetically H. cutirubrum is more closely related to the eukaryotes than to the eubacteria.

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