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Literature summary for 2.7.7.72 extracted from

  • Hoffmeier, A.; Betat, H.; Bluschke, A.; Gunther, R.; Junghanns, S.; Hofmann, H.J.; Morl, M.
    Unusual evolution of a catalytic core element in CCA-adding enzymes (2010), Nucleic Acids Res., 38, 4436-4447.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 2.7.7.72

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Escherichia coli
expression in Escherichia coli Geobacillus stearothermophilus
expression in Escherichia coli Homo sapiens

Crystallization (Commentary)

Crystallization (Comment) Organism
modeling of a loop sequence inserted into the structure of human CCA-adding enzyme based on pdb-entry 1OU5. The conserved loop residue R105 forms a salt bridge to the first residue E164 of the amino acid template EDxxR in motif D Homo sapiens

Protein Variants

Protein Variants Comment Organism
additional information replacement of residues 100-117 in the human enzyme by the corresponding part of the Escherichia coli enzyme, positions 66-87, leading to the chimera HEH with human enzyme N-terminus, Escherichia coli flexible loop, human enzyme C-terminus. Replacement of the region in the Escherichia coli enzyme by either the human loop element, representing the reciprocal experiment, chimera EHE, or by the Bacillus stearothermophilus part, resulting in chimera EBE. Whereas the wild-type enzymes incorporate the complete CCA sequence, the chimeric enzymes EHE, HEH and EBE show a reduced activity and add only 2 C residues to the tRNA substrate. The chimeras EHE, HEH show a 45-to 145fold reduced kcat for A-incorporation. The corresponding KM values are consistent with the KM values of the loop donor enzymes Escherichia coli
additional information replacement of residues 100117 in the human enzyme by the corresponding part of the Escherichia coli enzyme, positions 6687, leading to the chimera HEH with human enzyme N-terminus, Escherichia coli flexible loop, human enzyme C-terminus. Replacement of the region in the Escherichia coli enzyme by the human loop element, representing the reciprocal experiment, chimera EHE. Whereas the wild-type enzymes incorporate the complete CCA sequence, the chimeric enzymes EHE, HEH show a reduced activity and add only 2 C residues to the tRNA substrate. The chimeras EHE, HEH show a 45- to 145fold reduced kcat for A-incorporation. The corresponding KM values are consistent with the KM values of the loop donor enzymes Homo sapiens
additional information replacement of residues 66-87 in the Escherichia coli enzyme by the Bacillus stearothermophilus loop element, resulting in chimera EBE. Whereas the wild-type enzymes incorporate the complete CCA sequence, the chimeric enzyme EBE shows a reduced activity and adds only 2 C residues to the tRNA substrate. The chimera EBE shows a reduced kcat for A-incorporation. The corresponding KM value is consistent with the KM values of the loop donor enzymes Geobacillus stearothermophilus

Organism

Organism UniProt Comment Textmining
Escherichia coli
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Geobacillus stearothermophilus
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Homo sapiens Q96Q11
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-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Escherichia coli yeast tRNAPhe with 3'-CCA end + 3 diphosphate
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 ?
yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Geobacillus stearothermophilus yeast tRNAPhe with 3'-CCA end + 3 diphosphate
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 ?
yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Homo sapiens yeast tRNAPhe with 3'-CCA end + 3 diphosphate
-
 ?

Subunits

Subunits Comment Organism
More class II enzymes found in bacteria and eukaryotes carry a flexible loop in their catalytic core required for switching the specificity of the nucleotide binding pocket from CTP- to ATP-recognition, with the existence of conserved loop families. Loop replacements within families do not interfere with enzymatic activity. Modeling experiments suggest specific interactions of loop positions with important elements of the protein, forming a lever-like structure Homo sapiens