Literature summary for 3.8.1.8 extracted from

Peat, T.S.; Newman, J.; Balotra, S.; Lucent, D.; Warden, A.C.; Scott, C.
The structure of the hexameric atrazine chlorohydrolase AtzA (2015), Acta Crystallogr. Sect. D, 71, 710-720.

Cloned(Commentary)

Cloned (Comment)	Organism
gene atzA, recombinant expression of His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3)	Pseudomonas sp.

Crystallization (Commentary)

Crystallization (Comment)	Organism
purified recombinant detagged wildtype and mutant enzymes, mixing of 11.6 mg/ml protein in 50 mM HEPES, pH 7.5, and 100 mM NaCl with a reservoir solution containing 5.5% w/v PEG 8000, 2.7% v/v diethylene glycol, 50 mM HEPES, pH 7.1 or 50 mM HEPES pH 7.3, 4.6% w/v PEG 10 000, at 8°C, resulting in two different crystal forms, X-ray diffraction structure determination and analysis at 2.8 A and 2.2 A resolution, respectively, modeling	Pseudomonas sp.

Crystallization (Comment)

Organism

purified recombinant detagged wildtype and mutant enzymes, mixing of 11.6 mg/ml protein in 50 mM HEPES, pH 7.5, and 100 mM NaCl with a reservoir solution containing 5.5% w/v PEG 8000, 2.7% v/v diethylene glycol, 50 mM HEPES, pH 7.1 or 50 mM HEPES pH 7.3, 4.6% w/v PEG 10 000, at 8°C, resulting in two different crystal forms, X-ray diffraction structure determination and analysis at 2.8 A and 2.2 A resolution, respectively, modeling

Pseudomonas sp.

Protein Variants

Protein Variants	Comment	Organism
A170T/M256I/P258T/Y261S	commercially prepared mutant gene	Pseudomonas sp.

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Fe2+	the AtzA hexamer contains one essential Fe2+ per monomer and active site	Pseudomonas sp.

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
315000	-	hexameric recombinant detagged enzyme, gel filtration	Pseudomonas sp.

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
atrazine + H2O	Pseudomonas sp.	-	4-(ethylamino)-2-hydroxy-6-(isopropylamino)-1,3,5-triazine + chloride	-	?

Organism

Organism	UniProt	Comment	Textmining
Pseudomonas sp.	P72156	gene atzA	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, gel filtration, tag cleavage by by thrombin proteolysis, and again gel filtration	Pseudomonas sp.

Reaction

Reaction	Comment	Organism	Reaction ID
atrazine + H2O = hydroxyatrazine + chloride	two plausible reaction mechanisms are proposed involving either bidentate (a) or mondentate (b) coordination of the atrazine Cl atom to the Fe2+ centre of the AtzA active site, comparisons, overview	Pseudomonas sp.	a

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
atrazine + H2O	-	Pseudomonas sp.	4-(ethylamino)-2-hydroxy-6-(isopropylamino)-1,3,5-triazine + chloride	-	?
additional information	AtzA can only hydrolyze triazine halides. The relatively high Km of AtzA, which is greater than the water solubility of atrazine, leads to a less efficient catalytic rate by the enzyme compared to the alternative dimeric chlorohydrolase TrzN	Pseudomonas sp.	?	-	?

Subunits

Subunits	Comment	Organism
hexamer	the AtzA hexamer is a trimer of dimers, (alphabeta)3, the dimer interface is significantly larger than the individual protomer interfaces used to make up the hexamer, three-dimensional structure analysis	Pseudomonas sp.

Synonyms

Synonyms	Comment	Organism
AtzA	-	Pseudomonas sp.

General Information

General Information	Comment	Organism
evolution	both enzyme AtzA and the alternative chlorohydrolase TrzN from Arthrobacter aurescens belong to the same large family of amidohydrolases, although they are so different physically and phylogenetically that it is likely that atrazine chlorohydrolase activity evolved independently in each enzyme, comparison of enzyme features, overview. In contrast to most other known hydrolytic dehalogenases, which use an active-site carboxylic acid (Asp) to displace the halide ion, the metal-dependent reaction mechanisms of AtzA and TrzN make these two enzyme lineages somewhat unusual in nature	Pseudomonas sp.
metabolism	the enzyme catalyzes the first and necessary step in the breakdown of atrazine by the soil organism Pseudomonas sp. strain ADP	Pseudomonas sp.
additional information	enzyme active site structure, overview. The channel, substrate-binding pocket and active site are comprised of His66, His68, Gln71, Phe84, Tyr85, Trp87, Leu88, Phe89, Val92, Tyr93, Asp128, Met155, Phe157, Met160, Asp161, Ile164, Gln165, Val168, Leu180, Ser182, Ile183, Met184, Ala216, Thr217, Thr219, Ala220, His243, Glu246, Asp250, His276, Leu305, Asp327, Asn328 and Ser331. Structure comparison of AtzA and the alternative chlorohydrolase TrzN from Arthrobacter aurescens, overview	Pseudomonas sp.
physiological function	the enzyme catalyzes dechlorination of atrazine	Pseudomonas sp.