Literature summary for 3.5.2.6 extracted from

Cha, S.S.; An, Y.J.
Crystal structure of EstSRT1, a family VIII carboxylesterase displaying hydrolytic activity toward oxyimino cephalosporins (2016), Biochem. Biophys. Res. Commun., 478, 818-824 .

Cloned(Commentary)

Cloned (Comment)	Organism
gene estSRT1, recombinant expression of His-tagged enzyme in Escherichia coli strain B834 (DE3) as selenomethionyl-EstSTR1	uncultured bacterium

Crystallization (Commentary)

Crystallization (Comment)	Organism
recombinant His-tagged selenomethionyl-labeled EstSTR1 free and with bound PMSF, vapor batch crystallization method, mixing of 9 mg/ml protein and 1 mM PMSF with reservoir solution containing 25% w/v polyethylene glycol 3350, 100-mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (pH 7.5), and 200-mM NaCl, 22°C, X-ray diffraction structure determination and analysis at 2.0 A resolution	uncultured bacterium

Crystallization (Comment)

Organism

recombinant His-tagged selenomethionyl-labeled EstSTR1 free and with bound PMSF, vapor batch crystallization method, mixing of 9 mg/ml protein and 1 mM PMSF with reservoir solution containing 25% w/v polyethylene glycol 3350, 100-mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (pH 7.5), and 200-mM NaCl, 22°C, X-ray diffraction structure determination and analysis at 2.0 A resolution

uncultured bacterium

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
a beta-lactam + H2O	uncultured bacterium	-	a substituted beta-amino acid	-	?
additional information	uncultured bacterium	hydrolytic activities of two metagenome-derived family VIII carboxylesterases (EstSRT1 and EstU1) toward diverse esters and beta-lactam antibiotics, overview. Although EstSRT1 and EstU1 exhibit similar activities toward the hydrolysis of ester substrates, their activities toward beta-lactam antibiotics differ. EstU1 hydrolyzes first-generation cephalosporins, whereas EstSRT1 has activity toward first-, third-, and fourth-generation cephalosporins	?	-	?

Organism

Organism	UniProt	Comment	Textmining
uncultured bacterium	-	metagenome-derived family VIII carboxylesterase	-
uncultured bacterium	A0A0G2RKR9	beta-lactamase domain, cf. EC 3.1.1.1; metagenome-derived family VIII carboxylesterase	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His-tagged selenomethionyl-EstSTR1 from Escherichia coli strain B834 (DE3) by affinity chromatography and gel filtration	uncultured bacterium

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
a beta-lactam + H2O	-	uncultured bacterium	a substituted beta-amino acid	-	?
cefepime + H2O	-	uncultured bacterium	(2R)-2-[(R)-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-(methoxyimino)acetyl]amino](carboxy)methyl]-5-[(1-methylpyrrolidinium-1-yl)methyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylate	-	?
cefotaxime + H2O	-	uncultured bacterium	(2R)-5-[(acetyloxy)methyl]-2-[(R)-[[(2E)-2-(2-amino-1,3-thiazol-4-yl)-2-(methoxyimino)acetyl]amino](carboxy)methyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid	-	?
ceftazidime + H2O	-	uncultured bacterium	(2R)-2-[(R)-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-[[(2-carboxypropan-2-yl)oxy]imino]acetyl]amino](carboxy)methyl]-5-(pyridinium-1-ylmethyl)-3,6-dihydro-2H-1,3-thiazine-4-carboxylate	-	?
cephalothin + H2O	binding mode of cephalothin, overview	uncultured bacterium	(2R)-5-[(acetyloxy)methyl]-2-[(R)-carboxy[(thiophen-2-ylacetyl)amino]methyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid	-	?
additional information	hydrolytic activities of two metagenome-derived family VIII carboxylesterases (EstSRT1 and EstU1) toward diverse esters and beta-lactam antibiotics, overview. Although EstSRT1 and EstU1 exhibit similar activities toward the hydrolysis of ester substrates, their activities toward beta-lactam antibiotics differ. EstU1 hydrolyzes first-generation cephalosporins, whereas EstSRT1 has activity toward first-, third-, and fourth-generation cephalosporins	uncultured bacterium	?	-	?
additional information	enzyme EstSRT1 displays the broadest substrate specificity among family VIII carboxylesterases with beta-lactamase activity	uncultured bacterium	?	-	?

Synonyms

Synonyms	Comment	Organism
EstSRT1	-	uncultured bacterium
metagenome-derived family VIII carboxylesterase	-	uncultured bacterium

General Information

General Information	Comment	Organism
evolution	EstSRT1 is a family VIII carboxylesterase. The enzyme contains a large alpha/beta domain and a small alpha-helical domain and harbors three catalytic residues, Ser71, Lys74, and Tyr160, in the cavity at the domain interface, similarly to other family VIII carboxylesterases. Comparison of the structures of EstSRT1 and EstU1, a family VIII carboxylesterase with no hydrolytic activity toward bulky oxyimino cephalosporins, reveals that EstSRT1 has a smaller active site, despite its extended substrate range. The B-factors of the active site segments that can potentially contact with the oxyimino groups and the R2 side chains of oxyimino cephalosporins are higher in EstSRT1 than in EstU1, thus suggesting the role of the active site's structural flexibility in the extension of EstSRT1's substrate spectrum	uncultured bacterium
additional information	structural basis of the hydrolytic activity of EstSRT1 toward bulky oxyimino antibiotics. Structural comparison between EstSRT1 and the EstU1/cephalothin complex	uncultured bacterium
additional information	structural basis of the hydrolytic activity of EstSRT1 toward bulky oxyimino antibiotics. The three catalytic residues are Ser71, Lys74, and Tyr160. Structural comparison between EstSRT1 and the EstU1/cephalothin complex	uncultured bacterium