Literature summary for 2.3.1.30 extracted from

Verma, D.; Gupta, S.; Saxena, R.; Kaur, P.; R, R.; Srivastava, S.; Gupta, V.
Allosteric inhibition and kinetic characterization of Klebsiella pneumoniae CysE an emerging drug target (2019), Int. J. Biol. Macromol., 151, 1240-1249 .

Application

Application	Comment	Organism
drug development	the essential requirement of serine acetyltransferase (SAT/CysE) for survival of several human pathogens makes it a very promising target for inhibitor designing and drug discovery, structure-based drug development, overview	Klebsiella pneumoniae

Cloned(Commentary)

Cloned (Comment)	Organism
gene cysE, recombinant expression of His6-tagged enzyme in Escherichia coli strain BL21(DE3)	Klebsiella pneumoniae

Crystallization (Commentary)

Crystallization (Comment)	Organism
purified His-tagged enzyme in complex with L-cysteine, mixing of 0.002 ml of 30 mg/ml protein in 20 mM Tris pH 8.0; 50 mM NaCl and 5% glycerol, with 0.0016 ml of reservoir solution with 400 nl 3% w/v trimethylamine N-oxide dehydrate additive and 25% ethylene glycol as precipitant, and equilibration against reservoir solution, 20°C, X-ray diffraction structure determination and analysis at 2.8 A resolution, molecular replacement using Escherichia coli CysE hexameric structure (PDB ID 1T3D) as a search model	Klebsiella pneumoniae

Crystallization (Comment)

Organism

purified His-tagged enzyme in complex with L-cysteine, mixing of 0.002 ml of 30 mg/ml protein in 20 mM Tris pH 8.0; 50 mM NaCl and 5% glycerol, with 0.0016 ml of reservoir solution with 400 nl 3% w/v trimethylamine N-oxide dehydrate additive and 25% ethylene glycol as precipitant, and equilibration against reservoir solution, 20°C, X-ray diffraction structure determination and analysis at 2.8 A resolution, molecular replacement using Escherichia coli CysE hexameric structure (PDB ID 1T3D) as a search model

Klebsiella pneumoniae

Inhibitors

Inhibitors	Comment	Organism
apocynin	41% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae
Berberine	the ligand binds at the trimer-trimer interface, 24% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae
L-cysteine	a feedback inhibitor, binding structure from crystal structure analysis of the enzyme-bound complex. A cysteine molecule bound at the active site pocket at the interface of two Kpn CysE subunits. Each Kpn CysE trimer in-houses three cysteine molecules at the equivalent sites related by a 3fold axis, that, in turn, are related to remaining 3 active sites by 2 fold symmetry. Cysteine at the interface of two subunits is stabilized by interactions from one subunit involving Asp92, Pro93 and Ala94 (residues of turn connecting alpha5 and alpha6 helices) and Asp157, His158 (residues of L?betaloop) as well as from Gly183, Gly184, Thr185, Arg192, His193 (residues of substrate binding loop) of the adjacent subunit. About 50% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae
mangiferin	the ligand is involved in hydrophilic as well as hydrophobic interactions with enzyme Kpn CysE, 22% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae
additional information	structural information of a ligand-bound receptor complex via molecular dynamics simulation, docking study, overview	Klebsiella pneumoniae
quercetin	uncompetitive inhibitor, molecular dynamics simulations carried out to elucidate the binding mode of quercetin reveal that this small molecule binds at the trimer-trimer interface of hexameric CysE, a site physically distinct from the active site of the enzyme, overview. Binding of quercetin to CysE leads to conformation changes in the active site loops and proximal loops that affect its internal dynamics and consequently its affinity for substrate/co-factor binding, justifying the reduced enzyme activity. Quercetin binding kinetics and analysis provide mechanistic understanding of allosteric modulation. The ligand is involved in hydrophilic as well as hydrophobic interactions with Kpn CysE, 62% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae
vasicine	the ligand binds at the trimer-trimer interface, 46% inhibition at 0.005 mM with 500 ng enzyme	Klebsiella pneumoniae

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
additional information	-	additional information	Michalis-Menten kinetics	Klebsiella pneumoniae

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
acetyl-CoA + L-serine	Klebsiella pneumoniae	-	CoA + O-acetyl-L-serine	-	?

Organism

Organism	UniProt	Comment	Textmining
Klebsiella pneumoniae	Q0ZB96	-	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His6-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, dialysis, and ultrafiltration	Klebsiella pneumoniae

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
acetyl-CoA + L-serine	-	Klebsiella pneumoniae	CoA + O-acetyl-L-serine	-	?

Subunits

Subunits	Comment	Organism
hexamer	enzyme CysE has a trimer-trimer interface, two trimers are stacked on each other in head-to-head position through hydrophobic interactions at the N-terminus	Klebsiella pneumoniae

Synonyms

Synonyms	Comment	Organism
CysE	-	Klebsiella pneumoniae
Kpn CysE	-	Klebsiella pneumoniae
SAT	-	Klebsiella pneumoniae
serine acetyltransferase	-	Klebsiella pneumoniae

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	assay at	Klebsiella pneumoniae

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
8	-	assay at	Klebsiella pneumoniae

Cofactor

Cofactor	Comment	Organism	Structure
acetyl-CoA	-	Klebsiella pneumoniae

Ki Value [mM]

Ki Value [mM]	Ki Value maximum [mM]	Inhibitor	Comment	Organism	Structure
additional information	-	additional information	inhibition kinetics	Klebsiella pneumoniae

IC50 Value

IC50 Value	IC50 Value Maximum	Comment	Organism	Inhibitor	Structure
0.0037	-	pH 8.0, 25°C, recombinant enzyme	Klebsiella pneumoniae	quercetin

General Information

General Information	Comment	Organism
metabolism	enzyme CysE is involved in the cysteine biosynthetic pathway	Klebsiella pneumoniae
physiological function	in the two-step cysteine biosynthetic pathway, CysE/SAT (serine acetyltransferase) transfers acetyl moiety from acetyl-CoA to L-serine resulting in O-acetyl serine (OAS). Subsequently, pyridoxal 5'-phosphate-dependent O-acetyl serine sulfhydralase (OASS), also known as CysK, transfers reduced sulfide to OAS in a beta-replacement reaction yielding L-cysteine	Klebsiella pneumoniae