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Literature summary for 5.6.2.4 extracted from

  • Bagchi, D.; Manosas, M.; Zhang, W.; Manthei, K.A.; Hodeib, S.; Ducos, B.; Keck, J.L.; Croquette, V.
    Single molecule kinetics uncover roles for E. coli RecQ DNA helicase domains and interaction with SSB (2018), Nucleic Acids Res., 46, 8500-8515 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 5.6.2.4

Activating Compound

Activating Compound Comment Organism Structure
ssDNA-binding protein SSB, inclusion of Escherichia coli ssDNA-binding protein (SSB) induces a third fast unwinding mode four times faster than the normal RecQ mode and enhances the overall helicase activity (affinity, rate, and processivity). SSB stimulation is, furthermore, observed in the RecQ deletion mutants, including the variant missing the WH domain. Escherichia coli SSB interacts with RecQ using the conserved and structurally dynamic SSB C-terminal sequence (SSB-Ct, Met-Asp-Phe-Asp-Asp-Asp-Ile-Pro-Phe) Escherichia coli

Protein Variants

Protein Variants Comment Organism
additional information generation of several truncated RecQ enzyme mutants, i.e. RecQ-DELTAC and RecQ-DELTADELTAC proteins. The strand-switching behavior is observed with RecQ proteins that contain a WH domain (wild-type RecQ and RecQ-DELTAC) but not in the variant lacking the WH domain. Structure-function analysis of wild-type and mutant RecQ enzymes, overview. SSB strongly stimulates the unwinding activity of the RecQ-DELTADELTAC protein Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information Michaelis-Menten kinetics Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ATP + H2O Escherichia coli
-
 ADP + phosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli P15043
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + H2O
-
 Escherichia coli ADP + phosphate
-
 ?
ATP + H2O rates of DNA unwinding catalyzed by wild-type RecQ and truncated RecQ mutants are measured at the single molecule level using a 1.2 kb hairpin ssDNA substrate, method, overview Escherichia coli ADP + phosphate
-
 ?

Subunits

Subunits Comment Organism
More Escherichia coli RecQ contains three evolutionarily conserved domains: helicase domain, RecQC domain, and helicase-and-RNase-D-C-terminal (HRDC) domain. The WH domain plays a role in DNA binding and in DNA unwinding Escherichia coli

Synonyms

Synonyms Comment Organism
REcQ
-
 Escherichia coli
RecQ DNA helicase
-
 Escherichia coli
RecQ helicase
-
 Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
29
-
 assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.6
-
 assay at Escherichia coli

General Information

General Information Comment Organism
additional information some unwinding events occur with a uniform rate, denoted as the normal (N) mode whereas other events present a slower and non-uniform unwinding rate denoted as the slow (S) mode. This bimodal behavior has not been previously identified in ensemble assays. The N mode is characterized by a uniform rate of 62 bp/s at saturating ATP and 29°C (90 bp/s at 37°C), whereas the S mode unwinding is characterized by frequent pauses and backtracks in an apparent persistent random walk at a rate of 15-25 bp/s at 29°C. Individual helicases can switch between the two modes within a single event. Wild-type RecQ can also pass the loop apex of the DNA hairpin and continue translocating on the ssDNA produced by unwinding. In this case, the extent to which the hairpin refolds is dictated by the position of the helicase, which blocks DNA reannealing at the enzyme position. The WH domain plays a role in DNA binding and in DNA unwinding. Structure-function analysis of wild-type and mutant RecQ enzymes, detailed overview. The strand-switching behavior is observed with RecQ proteins that contain a WH domain (wild-type RecQ and RecQ-DELTAC) but not in the variant lacking the WH domain Escherichia coli
physiological function RecQ DNA helicases are motor proteins that convert the chemical energy of ATP hydrolysis to the mechanical energy required for single-stranded (ss) DNA translocation or double-stranded (ds) DNA unwinding. These activities are critical for RecQ's roles in genome maintenance in organisms ranging from bacteria to humans. In Escherichia coli, RecQ is a component of the RecF pathway of recombinational repair, which repairs ssDNA gaps and dsDNA breaks when the main repair pathway, RecBCD, is inactivated by mutation. ssDNA-binding protein (SSB) is the classical partner of helicases, which slows down DNA re-annealing by sequestering ssDNA. ssDNA and dsDNA binding sites play a crucial role in helicase activity, overview Escherichia coli