EG10586 sflamen

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Author Information

Steph Flamen

Basic Information

  • ID: EG10586
  • Name: metG
  • Organism: E. coli
  • Description: The metG gene encodes the Methionine—tRNA ligase enzyme which belongs to a family of aminoacyl tRNA synthases (catalyze the linking of molecules). ATP hydrolysis drives these synthases to link amino acids to their corresponding tRNA molecules by interpreting the mRNA. This enzyme, specifically, facilitates the reaction that couples methionine to methionyl-tRNA in the tRNA charging pathway, which groups E. coli tRNA charging reactions (reactions that load tRNA with the amino acid). It is essential for the initiation of mRNA translation and for the elongation of protein synthesis. [1] [2]
  • DNA Length: 2,034 base pairs.
  • DNA sequence:


  • Amino Acid length: 677 amino acids.
  • Amino Acid sequence:


Function and Homologs

  • Product: Methionine—tRNA ligase
  • Closest homologous proteins: The top (max three) homologous proteins to this protein, as identified by BLAST searches.
    • MULTISPECIES: methionine--tRNA ligase [Enterobacteriaceae], 1419/100%/0.0/100%, [3]
    • methionine--tRNA ligase [Shigella boydii], 1416/100%/0.0/99%, [4]
    • MULTISPECIES: methionine--tRNA ligase [Proteobacteria], 1415/100%/0.0/99%, [5]


  • Expression Level: High-2572 protein copies/cell (source: E. Coli Proteome Dataset)
  • Expression Level Hypothesis: This gene should be expressed at a high level because of its important role in interpreting the DNA code by linking amino acids to the appropriate tRNAs. It is also relevant to note that research shows that expression levels are enhanced in different strains of E. coli and that this level is coupled to the growth rate [6]. Methionine is also used relatively frequently in E. Coli [7], and perhaps can explain why metG is expressed at a higher level in E. Coli than in mycoides. [8]
  • Expression Level References and Description: I found expression level information for this exact gene in the E. coli dataset and the description of the gene's function here: [9]. Given that this dataset encapsulates measured levels of all expressed proteins under different growth conditions, I believe this expression level is accurate.
  • Expression Time: Right at the beginning
  • Expression Level Hypothesis: Because this gene encodes methionyl-tRNA synthase which is essential for the initiation of mRNA translation and elongation of protein synthesis, this gene is directly involved in the central dogma of biology and thus must be expressed right at the beginning. Specifically, this enzyme catalyzes the reaction that couples methionine to methionyl-tRNA; because methionine is a start codon, it is especially important that metG is expressed at the beginning. [10]
  • Expression Time References and Description: As stated in the hypothesis, this gene should be expressed at the beginning because it is needed for translation—part of the central dogma—which must happen right away. I used information about the gene's function that I found here: [11].

Gene Context

  • Other Components: This enzyme acts independently to link an amino acid to its corresponding tRNA molecule (single subunit); no other components are required for this catalyst to work. Mg2+ and Zn2+ are cofactors of this enzyme, though [12]. Although this is not a component, here is a link to another tRNA synthase EG10552.
  • Possible Dependencies: Methionine biosynthesis because methionine—tRNA ligase has no purpose without methionine.
  • Process: Coupling methionine to methionyl-tRNA [13]
    • Inputs: initiator tRNA(Met), L-methionine, ATP
    • Outputs: L-methionyl-[initiator tRNA(Met)], AMP, diphosphate


  • Synthesis Score: The synthesis score of your construct: 1, 2,3
  • Predicted Translation Rate: Prediction of construct translation rate from the RBS calculator
  • Design Notes and Details: For example, had to use a rare codon to fix folding energy;
  • GenBank File: A link to the GenBank file. file