PTCL1-EstA from Paenarthrobacter aurescens TC1, a Candidate for Industrial Application Belonging to the VIII Esterase Family

The esterase PTCL1-EstA from Paenarthrobacter aurescens TC1 was expressed in Escherichia coli and characterized. An 1152 bp open reading frame encoding a 383 amino acid polypeptide was successfully expressed, the C-terminally His6-tagged PTCL1-EstA enzyme was purified, and the predicted molecular mass of the purified PTCL1-EstA was 40.6 kDa. The EstA family serine hydrolase PTCL1-EstA belongs to the esterase family VIII, contains esterase-labeled S-C-S-K sequences, and homologous class C beta-lactamase sequences. PTCL1-EstA favored p-nitrophenyl esters with C2-C6 chain lengths, but it was also able to hydrolyze long-chain p-nitrophenyl esters. Homology modelling and substrate docking predicted that Ser59 was an active site residue in PTCL1-EstA, as well as Tyr148, Ala325, and Asp323, which are critical in catalyzing the enzymatic reaction of p-nitrophenyl esters. PTCL1-EstA reached the highest specific activity against p-nitrophenyl butyrate (C4) at pH 7.0 and 45 degrees C but revealed better thermal stability at 40 degrees C and maintained high relative enzymatic activity and stability at pH 5.0-9.0. Fermentation medium optimization for PTCL1-EstA increased the enzyme activity to 510.76 U/mL, tapping the potential of PTCL1-EstA for industrial production.

Automated summary

The esterase PTCL1-EstA from Paenarthrobacter aurescens TC1 was successfully expressed and purified. Homology modeling and substrate docking predicted the active site residues in PTCL1-EstA and its enzymatic activity and stability under different conditions were analyzed. Fermentation medium optimization increased the enzyme activity of PTCL1-EstA, showcasing its potential for industrial production.