Literature summary for 7.3.2.7 extracted from

Bhattacharjee, H.; Choudhury, R.; Rosen, B.P.
Role of conserved aspartates in the ArsA ATPase (2008), Biochemistry, 47, 7218-7227.

Activating Compound

Activating Compound	Comment	Organism	Structure
antimonite	activates 10fold the ATPase activity of wild-type ArsA, activation rates of mutants, overview	Escherichia coli
arsenite	activates 3fold the ATPase activity of wild-type ArsA, activation rates of mutants, overview	Escherichia coli

Cloned(Commentary)

Cloned (Comment)	Organism
expression of His6-tagged wild-type and mutant ArsA in Escherichia coli strain JM109. At high expression level wild-type ArsA is located in the cytosol, mutants D142A, D142E, and D142N are also found predominantly in the cytosol at similar levels as the wild type, but D447A and D447E proteins are found as insoluble aggregates, while only trace amounts of D447N can be observed in the soluble fraction	Escherichia coli

Cloned (Comment)

Organism

expression of His6-tagged wild-type and mutant ArsA in Escherichia coli strain JM109. At high expression level wild-type ArsA is located in the cytosol, mutants D142A, D142E, and D142N are also found predominantly in the cytosol at similar levels as the wild type, but D447A and D447E proteins are found as insoluble aggregates, while only trace amounts of D447N can be observed in the soluble fraction

Escherichia coli

Protein Variants

Protein Variants	Comment	Organism
D142A	site-directed mutagenesis, the mutant is activated by arsenite and antimonite in a similar amount as the wild-type enzyme	Escherichia coli
D142E	site-directed mutagenesis, the mutant is stronger activated by arsenite and antimonite compared to the wild-type enzyme	Escherichia coli
D142N	site-directed mutagenesis, the mutant is activated by arsenite and antimonite in a similar amount as the wild-type enzyme	Escherichia coli
D447A	site-directed mutagenesis, the mutant is less activated by arsenite and antimonite compared to the wild-type enzyme	Escherichia coli
D447E	site-directed mutagenesis, the mutant is less activated by arsenite and antimonite compared to the wild-type enzyme	Escherichia coli
D447N	site-directed mutagenesis, the near complete insolubility of D447N ArsA precludes its purification and biochemical characterization	Escherichia coli

Inhibitors

Inhibitors	Comment	Organism	Structure
Trypsin	trypsin cleaves the ArsA at Arg290 to produce a 32 kDa A1 fragment that is catalytically inactive and remains stable to trypsin digestion, and a slightly smaller A2 fragment which is digested rapidly. The trypsin digestion pattern is much different when all three ligands, ATP, Sb(III), and Mg2+, are added together, conditions that produce activated catalysis, overview	Escherichia coli

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
additional information	-	additional information	activation kinetics of wild-type and mutant enzymes, overview	Escherichia coli
0.035	-	ATP	recombinant wild-type enzyme	Escherichia coli
0.15	-	ATP	recombinant mutant D142E	Escherichia coli
0.2	-	ATP	recombinant mutant D447E	Escherichia coli
0.6	-	ATP	recombinant mutant D447A	Escherichia coli
0.9	-	ATP	recombinant mutant D142N	Escherichia coli
1.25	-	ATP	recombinant mutant D142A	Escherichia coli

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
membrane	-	Escherichia coli	16020	-

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	required, Asp142 is involved in Mg2+ binding	Escherichia coli

Natural Substrates/ Products (Substrates)

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

Organism

Organism	UniProt	Comment	Textmining
Escherichia coli	-	gene arsA	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His6-tagged wild-type and mutant ArsA from Escherichia coli strain JM109 to over 95% homogeneity by nickel affinity chromatography	Escherichia coli

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + H2O + arsenite/in	-	Escherichia coli	ADP + phosphate + arsenite/out	-	?
ATP + H2O + arsenite/in	Asp142 is involved in Mg2+ binding and also plays a role in signal transduction between the catalytic and activation domains. In contrast, Asp447 is not nearly as critical for Mg2+ binding as Asp142 but appears to be in communication between the metal and catalytic sites	Escherichia coli	ADP + phosphate + arsenite/out	-	?

Subunits

Subunits	Comment	Organism
More	ArsA is composed of two homologous halves A1 and A2, each containing a nucleotide binding domain, and a single metalloid binding or activation domain is located at the interface of the two halves of the protein. The metalloid binding domain is connected to the two nucleotide binding domains through two DTAPTGH sequences, one in A1 and the other in A2. The DTAPTGH sequences are proposed to be involved in information communication between the metal and catalytic sites	Escherichia coli

Synonyms

Synonyms	Comment	Organism
ArsA ATPase	-	Escherichia coli

Cofactor

Cofactor	Comment	Organism	Structure
ATP	-	Escherichia coli