Identification and characterization of a novel salt-tolerant esterase from a Tibetan glacier metagenomic library.
A salt-tolerant esterase, designated H9Est, was identified from a metagenomic library of the Karuola glacier. H9Est gene comprised 1071 bp and encoded a polypeptide of 357 amino acids with a molecular mass of 40 kDa. Sequence analysis revealed that H9Est belonged to the family IV of bacterial lypolitic enzyme. H9Est was overexpressed in Escherichia coli and the purified enzyme showed hydrolytic activity towards p-nitrophenyl esters with carbon chain from 2 to 8. The optimal esterase activity was at 40°C and pH 8.0 and the enzyme retained its activity towards some miscible organic solvents such as polyethylene glycol. A three-dimensional model of H9Est revealed that S200, D294, and H324 formed the H9Est catalytic triad. Circular Dichroism spectra and molecular dynamic simulation indicated that the esterase had a wide denaturation temperature range and flexible loops that would be beneficial for H9Est performance at low temperatures while retaining heat-resistant features.
Inst. of Protein Biochemistry, National Research Council, Naples, I-80131, Italy.
Concetta
C
De Santi
Inst. of Protein Biochemistry, National Research Council, Naples, I-80131, Italy.
Luca
L
Ambrosino
Inst. of Protein Biochemistry, National Research Council, Naples, I-80131, Italy.
Pietro
P
Tedesco
Lei
L
Zhai
Cheng
C
Zhou
Yanfen
Y
Xue
State Key Laboratory of Microbial Resources and National Engineering Laboratory for Industrial Enzymes, Inst. of Microbiology, CAS, Beijing, 100101, China.
Yanhe
Y
Ma
Donatella
D
de Pascale
D000595:Amino Acid Sequence; D001709:Biotechnology; D003080:Cold Temperature; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D004950:Esterases / Q000737:chemistry* / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015723:Gene Library; D046448:Ice Cover / Q000382:microbiology*; D054892:Metagenome / Q000235:genetics*; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance / Q000235:genetics*; D016415:Sequence Alignment
D011994:Recombinant Proteins; D004950:Esterases
cold-tolerant; esterase; metagenomic; salt-tolerant