Ksenia Novototskaya-Vlasova

Russian Academy of Sciences, Moscow, Moscow, Russia

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Publications (2)4.99 Total impact

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    ABSTRACT: We describe cloning and expression of genes coding for lipase Lip2Pc and lipase-specific foldase LifPc from a psychrotrophic microorganism Psychrobacter cryohalolentis K5(T) isolated from a Siberian cryopeg (the lense of overcooled brine within permafrost). Upon expression in E. coli Lip2Pc accumulated in inclusion bodies while chaperone was synthesized in a soluble form. An efficient protocol for solubilization and subsequent refolding of the recombinant lipase in the presence of the truncated chaperone was developed. Using this procedure Lip2Pc with specific activity of 6900 U/mg was obtained. Contrary to published data on other lipase-chaperone complexes, refolded Lip2Pc was mostly recovered from the complex with chaperone by metal-affinity chromatography. Recombinant Lip2Pc displayed maximum lipolytic activity at 25°C and pH 8.0 with p-nitrophenyl palmitate (C16) as a substrate. Activity assays conducted at different temperatures revealed that the recombinant Lip2Pc is a cold-adapted lipase with ability to utilize substrates with long (C10-C16) hydrocarbon chains in the temperature range from +5 to +65°C. It demonstrated relatively high stability at temperatures above 60°C and in the presence of various metal ions or organic solvents (ethanol, methanol, etc.). Non-ionic detergents, such as Triton X-100 and Tween 20 decreased Lip2Pc activity and SDS completely inhibited it.
    Protein Expression and Purification 07/2013; · 1.43 Impact Factor
  • Ksenia Novototskaya-Vlasova, Lada Petrovskaya, Sergey Yakimov, David Gilichinsky
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    ABSTRACT: A psychrotrophic gram-negative bacterium Psychrobacter cryohalolentis K5(T) was previously isolated from a cryopeg within Siberian permafrost and its genome has been completely sequenced. To clone and characterize potential cold-active lipases/esterases produced by P. cryohalolentis K5(T) , we have identified their potential genes by alignment with amino acid sequences of lipases/esterases from related bacteria. One of the targets, EstPc, was cloned and overexpressed in Escherichia coli BL21 (DE3) cells. The recombinant protein was produced with a 6x histidine tag at its C-terminus and purified by nickel affinity chromatography. Purified recombinant protein displayed maximum esterolytic activity with p-nitrophenyl butyrate (C4) as a substrate at 35 °C and pH 8.5. Activity assay conducted at different temperatures revealed that EstPc is a cold-adapted esterase which displayed more than 90% of its maximum activity at 0-5 °C. In contrast to many known cold-active enzymes, it possesses relatively high thermostability, preserving more than 60% of activity after incubation for 1 h at 80 °C. It was activated by Ca(2+) , Mn(2+) , and EDTA whereas Zn(+2) , Cu(+2) , Co(+2) , Ni(+2) , and Mg(+2) inhibited it. Various organic solvents (ethanol, methanol and others) inhibited the enzyme. Most non-ionic detergents, such as Triton X-100 and Tween 20 increased the lipase activity while SDS completely inhibited it.
    FEMS Microbiology Ecology 04/2012; 82(2):367-75. · 3.56 Impact Factor