Literature summary for 2.3.1.221 extracted from

Vagstad, A.L.; Bumpus, S.B.; Belecki, K.; Kelleher, N.L.; Townsend, C.A.
Interrogation of global active site occupancy of a fungal iterative polyketide synthase reveals strategies for maintaining biosynthetic fidelity (2012), J. Am. Chem. Soc., 134, 6865-6877.

Search for more literature for 2.3.1.221

Cloned(Commentary)

Cloned (Comment)	Organism
expression of N-terminally His6-tagged enzyme domains in Escherichia coli strain BL21(DE3)	Aspergillus parasiticus

Protein Variants

Protein Variants	Comment	Organism
S1937A	inactive mutant	Aspergillus parasiticus

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
1.46	-	hexanoyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus
15.38	-	acetyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
7 malonyl-CoA + hexanoyl-[acyl-carrier protein]	Aspergillus parasiticus	-	7 CoA + norsolorinic acid anthrone + [acyl-carrier protein] + 7 CO2 + 2 H2O	-	?

Organism

Organism	UniProt	Comment	Textmining
Aspergillus parasiticus	-	-	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant N-terminally His6-tagged enzyme domains from Escherichia coli strain BL21(DE3)	Aspergillus parasiticus

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
7 malonyl-CoA + acetyl-[acyl-carrier protein]	-	Aspergillus parasiticus	?	-	?
7 malonyl-CoA + hexanoyl-[acyl-carrier protein]	-	Aspergillus parasiticus	7 CoA + norsolorinic acid anthrone + [acyl-carrier protein] + 7 CO2 + 2 H2O	-	?
7 malonyl-CoA + hexanoyl-[acyl-carrier protein]	ACP-bound intermediates and major products of the reaction, overview	Aspergillus parasiticus	7 CoA + norsolorinic acid anthrone + [acyl-carrier protein] + 7 CO2 + 2 H2O	-	?
additional information	processivity of polyketide extension and substrate specificity, overview. The enzyme shows activity against hexanoyl- and acetyl-, but not malonyl-CoA. Rapid loading of extension units onto the carrier domain facilitates efficient chain extension in a manner kinetically favorable to ultimate product formation. Essential roles of the product template and thioesterase domains for cyclization and product release, editing role for the thioesterase domain	Aspergillus parasiticus	?	-	?

Subunits

Subunits	Comment	Organism
More	PksA domain structure, from N- to C-terminus including the starter unit: acylcarrier protein transacylase (SAT), beta-ketoacyl synthase (KS), malonyl-CoA: acyl-carrier protein transacylase (MAT), product template (PT), acyl-carrier protein (ACP), and thioesterase/Claisen cyclase (TE/CLC)	Aspergillus parasiticus

Synonyms

Synonyms	Comment	Organism
norsolorinic acid anthrone-producing polyketide synthase	-	Aspergillus parasiticus
PksA	-	Aspergillus parasiticus

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
22	-	assay at room temperature	Aspergillus parasiticus

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism	Structure
0.0407	-	acetyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus
0.0472	-	hexanoyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7	-	assay at	Aspergillus parasiticus

General Information

General Information	Comment	Organism
metabolism	the the norsolorinic acid anthrone-producing polyketide synthase, PksA, is involved in the aflatoxin biosynthetic pathway in Aspergillus parasiticus	Aspergillus parasiticus
additional information	the enzyme also has an editing function for the C-terminal thioesterase domain beyond its synthetic role in Claisen/Dieckmann cyclization and product release. Domain architecture and expected enzyme-bound intermediates of PksA, overview	Aspergillus parasiticus

kcat/KM [mM/s]

kcat/KM Value [1/mMs^-1]	kcat/KM Value Maximum [1/mMs^-1]	Substrate	Comment	Organism	Structure
0.0026	-	acetyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus
0.032	-	hexanoyl-[acyl-carrier protein]	pH 7.0, 22°C	Aspergillus parasiticus

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Release 2023.1 (January 2023)