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Literature summary for 3.1.11.5 extracted from

  • Amundsen, S.K.; Smith, G.R.
    The RecB helicase-nuclease tether mediates Chi hotspot control of RecBCD enzyme (2019), Nucleic Acids Res., 47, 197-209 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 3.1.11.5

Cloned(Commentary)

Cloned (Comment) Organism
genes recBCD, recombinant expression in Escherichia coli strain V2831 Escherichia coli

Protein Variants

Protein Variants Comment Organism
additional information deletion of amino acids 881-899 (DELTA19) of RecB, the entire tether. The resulting mutant DELTA19 is recombination-deficient and has no detectable Chi activity. The mutant retained nuclease activity, demonstrating that it is not a null mutant. Additional construction of RecB mutants lacking one or another part of the tether. Inserting two foreign tethers, to make the tether 57 amino acids long, both reduce Chi activity and recombination proficiency to about the same level as that of RecBCD with the 38-amino-acid tethers. None of the mutants reported increases Chi hotspot activity. RecBCD enzymatic activities coincide with the genetic activities of the tether mutants Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
additional information the tether (amino acids 881-899 of RecB) amino-acid composition, like the tether length, can strongly affect the ability ofRecBCD to respond to Chi and to promote recombination Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli P08394 AND P07648 AND P04993 RecBCD enzyme subunits RecB, RecC, and RecD, i.e. beta-, gamma-, and alpha-subunits
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Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information when the concentration of ATP is greater than that of Mg2+ ions, RecBCD unwinds the DNA and nicks the Chi-containing strand of DNA a few nucleotides to the 3' side of the core sequence, continued unwinding produces 3'-ended ssDNA for strand exchange by RecA. When the concentration of Mg2+ ions is greater than that of ATP, RecBCD makes, during unwinding, occasional endonucleolytic nicks up to Chi on the 3'-ended strand, releasing fragments hundreds of nucleotides long, continued unwinding and similar nicking of the complementary strand produces 3'-ended ssDNA for strand exchange. A second round of RecBCD action is required to produce the acid-soluble, short oligonucleotides typically assayed as nuclease activity with purified enzyme and in repair-deficient cells (e.g. recA mutants) after DNA damage Escherichia coli ?
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Synonyms

Synonyms Comment Organism
RecB helicase-nuclease
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 Escherichia coli
RecBCD
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 Escherichia coli
recBCD enzyme
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 Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
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 assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
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 assay at Escherichia coli

Cofactor

Cofactor Comment Organism Structure
ATP when the concentration of ATP is greater than that of Mg2+ ions, RecBCD unwinds the DNA and nicks the Chi-containing strand of DNA a few nucleotides to the 3' side of the core sequence, continued unwinding produces 3'-ended ss DNA for strand exchange by RecA Escherichia coli

General Information

General Information Comment Organism
metabolism enzyme RecBCD's repair of DNA is controlled by Chi, overview Escherichia coli
additional information the tether (amino acids 881-899) of RecB is essential for Chi's stimulation of recombination. The tether can be lengthened somewhat without alteration of Chi's control, but a too-long tether significantly reduces Chi's control of RecBCD Escherichia coli
physiological function repair of DNA double-strand breaks uses a highly conserved helicase-nuclease complex to unwind DNA from a broken end and cut it at specific DNA sequences called Chi. In Escherichia coli the RecBCD enzyme also loads the DNA strand exchange protein RecA onto the newly formed end, resulting in a recombination hotspot at Chi. Chi hotspots regulate multiple RecBCD activities by altering RecBCD's conformation, which is proposed to include the swinging of the RecB nuclease domain on the 19-amino-acid tether connecting the helicase and nuclease domains. Proper control of RecBCD by Chi requires that the tether be long enough and appropriately flexible. A model, in which the swing-time of the nuclease domain determines the position of Chi-dependent and Chi-independent cuts and Chi hotspot activity, is established. Generation of a molecular model for Chi-dependent nuclease swinging, and predictions of the nuclease-swing model, overview Escherichia coli