Literature summary for 5.6.2.4 extracted from

Schroepfer, S.; Kobbe, D.; Hartung, F.; Knoll, A.; Puchta, H.
Defining the roles of the N-terminal region and the helicase activity of RECQ4A in DNA repair and homologous recombination in Arabidopsis (2014), Nucleic Acids Res., 42, 1684-1697.

Search for more literature for 5.6.2.4

Cloned(Commentary)

Cloned (Comment)	Organism
recombinant expression of His-tagged wild-type and mutant enzymes in Escherichia coli strain ER2566	Arabidopsis thaliana

Protein Variants

Protein Variants	Comment	Organism
K481M	site-directed mutagenesis in the Walker A motif of the helicase domain	Arabidopsis thaliana
additional information	the helicase core is able to regress an artificial replication fork. Swapping of the terminal regions of RECQ4A with the closely related but functionally distinct helicase RECQ4B indicates that in contrast to the C-terminus, the N-terminus of RECQ4A is required for its specific functions in DNA repair and recombination. Generation of diverse enzyme mutants and transgenic Arabidopsis thaliana plants, complementation of the recq4A-4 mutant, different RECQ4A constructs are cloned including a full-length wild-type construct (RECQ4A) and different variants of the RECQ4A ORF in which individual domains are modified or deleted, RECQ4A-HD, RECQ4A-DN, RECQ4A-DN-HD, RECQ-(4B)4A and RECQ-4A(4B), respectively. The recq4A-4 mutant is hypersensitive to treatment with cisplatin	Arabidopsis thaliana

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	required	Arabidopsis thaliana

Natural Substrates/ Products (Substrates)

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

Organism

Organism	UniProt	Comment	Textmining
Arabidopsis thaliana	Q8L840	-	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain ER2566 by nickel affinity chromatography	Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + H2O	-	Arabidopsis thaliana	ADP + phosphate	-	?

Synonyms

Synonyms	Comment	Organism
RecQ helicase	-	Arabidopsis thaliana
RECQ4A	-	Arabidopsis thaliana

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
37	-	assay at	Arabidopsis thaliana

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
8	-	assay at	Arabidopsis thaliana

General Information

General Information	Comment	Organism
malfunction	loss of RECQ4A leads to elevated homologous recombination frequencies and hypersensitivity to genotoxic agents. Loss of helicase activity or deletion of the N-terminus only partially complemented the mutant hyper-recombination phenotype. The helicase-deficient protein lacking its N-terminus does not complement the hyper-recombination phenotype at all. The recq4A-4 mutant is hypersensitive to treatment with cisplatin. The loss of RECQ4A also leads to a hypersensitivity to the DNA methylating agent MMS. Deletion of the RECQ4A N-terminus does not affect the viability of plants but results in a DNA repair defect	Arabidopsis thaliana
additional information	residue K481 in the Walker A box is an essential amino acid for the helicase activity of the enzyme. Both the N-terminal region and the helicase activity contribute to the suppression of homologous recombination, only the N-terminus, not the C-terminus, defines the functional specificity. Structure-function relationship analysis	Arabidopsis thaliana
physiological function	RecQ helicases are critical for the maintenance of genomic stability, RECQ4A performs critical roles in regulation of homologous recombination and DNA repair. The N-terminal region and the helicase activity of RECQ4A are both essential for the cellular response to replicative stress induced by methyl methanesulfonate and cisplatin. RECQ4A seems to possess at least two different and independent sub-functions involved in the suppression of homologous recombination	Arabidopsis thaliana

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Release 2023.1 (January 2023)