Literature summary for 2.5.1.47 extracted from

Lu, M.; Xu, B.Y.; Zhou, K.; Cheng, W.; Jiang, Y.L.; Chen, Y.; Zhou, C.Z.
Structural and biochemical analyses of Microcystis aeruginosa O-acetylserine sulfhydrylases reveal a negative feedback regulation of cysteine biosynthesis (2014), Biochim. Biophys. Acta, 1844, 308-315.

Cloned(Commentary)

Cloned (Comment)	Organism
gene cysK1, sequence comparisons, recombinant expression of N-terminally His6-tagged isozyme CysK1 in Escherichia coli strain BL21 (DE3)	Microcystis aeruginosa
gene cysK2, sequence comparisons, recombinant expression of N-terminally His6-tagged isozyme CysK2 in Escherichia coli strain BL21 (DE3)	Microcystis aeruginosa

Crystallization (Commentary)

Crystallization (Comment)	Organism
purified isozyme CysK1, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 0.1 M MOPS, pH 6.0, 60% 2-methyl-2,4-pentanediol, 16°C, X-ray diffraction structure determination and analysis at 2.30 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model	Microcystis aeruginosa
purified isozyme CysK2 in complex with cystine, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 1.5 M (NH4)2SO4, 0.1M Bis-Tris-propane, pH 7.0, and 10 mM cystine, 16°C, X-ray diffraction structure determination and analysis at 1.91 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model	Microcystis aeruginosa

Crystallization (Comment)

Organism

purified isozyme CysK1, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 0.1 M MOPS, pH 6.0, 60% 2-methyl-2,4-pentanediol, 16°C, X-ray diffraction structure determination and analysis at 2.30 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model

Microcystis aeruginosa

purified isozyme CysK2 in complex with cystine, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 1.5 M (NH4)2SO4, 0.1M Bis-Tris-propane, pH 7.0, and 10 mM cystine, 16°C, X-ray diffraction structure determination and analysis at 1.91 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model

Microcystis aeruginosa

Inhibitors

Inhibitors	Comment	Organism	Structure
cystine	competitive versus O-acetyl-L-serine, the cystine-binding residues are highly conserved in all OASS proteins; competitive versus O-acetyl-L-serine, the cystine-binding residues are highly conserved in all OASS proteins. Active site of CysK2cystine binding structure, overview. Cystine occupies the substrate/product binding site of the enzyme	Microcystis aeruginosa
trichloroacetic acid	inactivation at 16.6% v/v; inactivation at 16.6% v/v	Microcystis aeruginosa

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
1	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa
1.1	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa
1.8	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
2.3	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
3.5	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa
4.8	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
O-acetyl-L-serine + hydrogen sulfide	Microcystis aeruginosa	-	L-cysteine + acetate	-	?

Organism

Organism	UniProt	Comment	Textmining
Microcystis aeruginosa	A8YBP8	gene cysK2, IPF_3084, or CAO86589	-
Microcystis aeruginosa	A8YBS4	gene cysK1, IPF_2058, or cao86616	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant N-terminally His6-tagged isozyme CysK1 from Escherichia coli strain BL21 (DE3) by nickel affinity chromatography and ultrafiltration	Microcystis aeruginosa
recombinant N-terminally His6-tagged isozyme CysK2 from Escherichia coli strain BL21 (DE3) by nickel affinity chromatography and ultrafiltration	Microcystis aeruginosa

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
235	-	substrate O-acetyl-L-serine, purified recombinant isozyme CysK1, pH 7.0, 25°C	Microcystis aeruginosa
412	-	substrate O-acetyl-L-serine, purified recombinant isozyme CysK2, pH 7.0, 25°C	Microcystis aeruginosa

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
O-acetyl-L-serine + hydrogen sulfide	-	Microcystis aeruginosa	L-cysteine + acetate	-	?

Synonyms

Synonyms	Comment	Organism
O-acetylserine sulfhydrylase	-	Microcystis aeruginosa
OASS	-	Microcystis aeruginosa

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	-	Microcystis aeruginosa

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism
132	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa
136	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
140	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa
211	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
231	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa
232	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7	-	assay at	Microcystis aeruginosa

Cofactor

Cofactor	Comment	Organism	Structure
pyridoxal 5'-phosphate	dependent on, binding site structure analysis in a cleft between the N- and C-terminal domains, the phosphate group of PLP interacts with the highly conserved Gly/Thr-rich loop (G181TGGT185) and a water molecule, overview	Microcystis aeruginosa

General Information

General Information	Comment	Organism
evolution	the enzyme belongs to the family of fold-type II PLP-dependent enzymes. The cyanobacterium Microcystis aeruginosa PCC 7806 encodes three putative OASSs: CAO86616, CAO86589 and CAO86970, sequence comparisons	Microcystis aeruginosa
metabolism	the O-acetylserine sulfhydrylase catalyzes the final step of cysteine biosynthesis from O-acetylserine and inorganic sulfide, negative feedback regulation of the pathway. Autoinhibition by cystine might be a universal mechanism of cysteine biosynthesis pathway	Microcystis aeruginosa
metabolism	the O-acetylserine sulfhydrylase catalyzes the final step of cysteine biosynthesis from O-acetylserine and inorganic sulfide, negative feedback regulation of the pathway. Autoinhibition by cystine might be a universal mechanism of cysteine biosynthesis pathway, redox-dependent autoregulation	Microcystis aeruginosa
additional information	three-dimensional structure comparisons of isozymes CysK1 and CysK2, overview	Microcystis aeruginosa

kcat/KM [mM/s]

kcat/KM Value [1/mMs^-1]	kcat/KM Value Maximum [1/mMs^-1]	Substrate	Comment	Organism
39.8	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa
48.1	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with glutathione, GSSG	Microcystis aeruginosa
76.5	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
91.3	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C	Microcystis aeruginosa
136	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa
219	-	O-acetyl-L-serine	recombinant enzyme, pH 7.0, 25°C, with DTT	Microcystis aeruginosa