title: The environment shapes microbial enzymes: five cold-active and salt-resistant carboxylesterases from marine metagenomes.
abstract: Most of the Earth's biosphere is cold and is populated by cold-adapted microorganisms. To explore the natural enzyme diversity of these environments and identify new carboxylesterases, we have screened three marine metagenome gene libraries for esterase activity. The screens identified 23 unique active clones, from which five highly active esterases were selected for biochemical characterization. The purified metagenomic esterases exhibited high activity against α-naphthyl and p-nitrophenyl esters with different chain lengths. All five esterases retained high activity at 5 °C indicating that they are cold-adapted enzymes. The activity of MGS0010 increased more than two times in the presence of up to 3.5 M NaCl or KCl, whereas the other four metagenomic esterases were inhibited to various degrees by these salts. The purified enzymes showed different sensitivities to inhibition by solvents and detergents, and the activities of MGS0010, MGS0105 and MGS0109 were stimulated three to five times by the addition of glycerol. Screening of purified esterases against 89 monoester substrates revealed broad substrate profiles with a preference for different esters. The metagenomic esterases also hydrolyzed several polyester substrates including polylactic acid suggesting that they can be used for polyester depolymerization. Thus, esterases from marine metagenomes are cold-adapted enzymes exhibiting broad biochemical diversity reflecting the environmental conditions where they evolved.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E5, Canada.
authors.forename: Anatoli
authors.initials: A
authors.lastname: Tchigvintsev
authors.forename: Hai
authors.initials: H
authors.lastname: Tran
authors.forename: Ana
authors.initials: A
authors.lastname: Popovic
authors.forename: Filip
authors.initials: F
authors.lastname: Kovacic
authors.forename: Greg
authors.initials: G
authors.lastname: Brown
authors.forename: Robert
authors.initials: R
authors.lastname: Flick
authors.forename: Mahbod
authors.initials: M
authors.lastname: Hajighasemi
authors.forename: Olga
authors.initials: O
authors.lastname: Egorova
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Somody
authors.forename: Dmitri
authors.initials: D
authors.lastname: Tchigvintsev
authors.forename: Anna
authors.initials: A
authors.lastname: Khusnutdinova
authors.forename: Tatyana N
authors.initials: TN
authors.lastname: Chernikova
authors.forename: Olga V
authors.initials: OV
authors.lastname: Golyshina
authors.forename: Michail M
authors.initials: MM
authors.lastname: Yakimov
authors.forename: Alexei
authors.initials: A
authors.lastname: Savchenko
authors.forename: Peter N
authors.initials: PN
authors.lastname: Golyshin
authors.forename: Karl-Erich
authors.initials: KE
authors.lastname: Jaeger
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Yakunin
mesh_terms: D059001:Aquatic Organisms / Q000201:enzymology* / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003080:Cold Temperature; D020536:Enzyme Activators / Q000378:metabolism; D054892:Metagenome; D008969:Molecular Sequence Data; D011189:Potassium Chloride / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D020536:Enzyme Activators; D012965:Sodium Chloride; D011189:Potassium Chloride; D002265:Carboxylic Ester Hydrolases