title: Cloning, expression and characterization of a novel cold‑adapted  GDSL family esterase from Photobacterium sp. strain J15.
abstract: The gene encoding for a novel cold-adapted enzyme from family II of bacterial classification (GDSL family) was cloned from the genomic DNA of Photobacterium sp. strain J15 in an Escherichia coli system, yielding a recombinant 36 kDa J15 GDSL esterase which was purified in two steps with a final yield and purification of 38.6 and 15.3 respectively. Characterization of the biochemical properties showed the J15 GDSL esterase had maximum activity at 20 °C and pH 8.0, was stable at 10 °C for 3 h and retained 50 % of its activity after a 6 h incubation at 10 °C. The enzyme was activated by Tween-20, -60 and Triton-X100 and inhibited by 1 mM Sodium dodecyl sulphate (SDS), while β-mercaptoethanol and Dithiothreitol (DTT) enhanced activity by 4.3 and 5.4 fold respectively. These results showed the J15 GDSL esterase was a novel cold-adapted enzyme from family II of lipolytic enzymes. A structural model constructed using autotransporter EstA from Pseudomonas aeruginosa as a template revealed the presence of a typical catalytic triad consisting of a serine, aspartate, and histidine which was verified with site directed mutagenesis on active serine.
authors.affiliation: Enzyme and Microbial Technology Research Centre, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. mehr_sh_2008@yahoo.com
authors.forename: Mehrnoush Hadaddzadeh
authors.initials: MH
authors.lastname: Shakiba
authors.forename: Mohd Shukuri Mohamad
authors.initials: MS
authors.lastname: Ali
authors.forename: Raja Noor Zaliha Raja Abd
authors.initials: RN
authors.lastname: Rahman
authors.forename: Abu Bakar
authors.initials: AB
authors.lastname: Salleh
authors.forename: Thean Chor
authors.initials: TC
authors.lastname: Leow
mesh_terms: D000064:Acclimatization; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D010776:Photobacterium / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny
chemical_list: D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases