A cold-adapted esterase from psychrotrophic Pseudoalteromas sp strain 643A

作者：Cieslinski Hubert; Bialkowska Aneta M; Dlugolecka Anna; Daroch Maurycy; Tkaczuk Karolina L; Kalinowska Halina; Kur Jozef^*; Turkiewicz Marianna

来源：Archives of Microbiology, 2007, 188(1): 27-36.

DOI：10.1007/s00203-007-0220-2

• cold-adapted enzyme
• psychrotolerant bacterium
• esterases
• lipases
• GDSL esterase
• cloning

A psychrotrophic bacterium producing a cold-adapted esterase upon growth at low temperatures was isolated from the alimentary tract of Antarctic krill Euphasia superba Dana, and classified as Pseudoalteromonas sp. strain 643A. A genomic DNA library of strain 643A was introduced into Escherichia coli TOP10F', and screening on tributyrin-containing agar plates led to the isolation of esterase gene. The esterase gene (estA, 621 bp) encoded a protein (EstA) of 207 amino acid residues with molecular mass of 23,036 Da. Analysis of the amino acid sequence of EstA suggests that it is a member of the GDSL-lipolytic enzymes family. The purification and characterization of native EstA esterase were performed. The enzyme displayed 20-50% of maximum activity at 0-20 degrees C. The optimal temperature for EstA was 35 degrees C. EstA was stable between pH 9 and 11.5. The enzyme showed activity for esters of short- to medium-chain (C-4 and C-10) fatty acids, and exhibited no activity for long-chain fatty acid esters like that of palmitate and stearate. EstA was strongly inhibited by phenylmethylsulfonyl fluoride, 2-mercaptoethanol, dithiothreitol and glutathione. Addition of selected divalent ions e.g. Mg2+, Co2+ and Cu2+ led to the reduction of enzymatic activity and the enzyme was slightly activated (similar to 30%) by Ca2+ ions.

• 出版日期2007-7