Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past

PLoS One. 2017 Jul 25;12(7):e0181029. doi: 10.1371/journal.pone.0181029. eCollection 2017.

Abstract

A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain) allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase. Sequence alignment of known thermophilic lipases allowed design of degenerated consensus primers for amplification and cloning of the corresponding lipase, named LipJ. However, the cloned enzyme displayed maximum activity at 30°C and pH 7, showing a different profile from that observed in supernatants of the parental strain. Sequence analysis of the cloned protein showed a pentapeptide motif -GHSMG- distinct from that of thermophilic lipases, and much closer to that of esterases. Nevertheless, the 3D structural model of LipJ displayed the same folding as that of thermophilic lipases, suggesting a common evolutionary origin. A phylogenetic study confirmed this possibility, positioning LipJ as a new member of the thermophilic family of bacterial lipases I.5. However, LipJ clusters in a clade close but separated from that of Geobacillus sp. thermophilic lipases. Comprehensive analysis of the cloned enzyme suggests a common origin of LipJ and other bacterial thermophilic lipases, and highlights the most probable divergent evolutionary pathway followed by LipJ, which during the harsh past times would have probably been a thermophilic enzyme, having lost these properties when the environment changed to more benign conditions.

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Bacillus / chemistry
  • Bacillus / enzymology*
  • Bacillus / genetics
  • Bacillus / metabolism
  • Cloning, Molecular
  • Esterases / chemistry
  • Esterases / genetics
  • Esterases / isolation & purification
  • Esterases / metabolism*
  • Lipase / chemistry
  • Lipase / genetics
  • Lipase / isolation & purification
  • Lipase / metabolism*
  • Metals / metabolism
  • Models, Molecular
  • Phylogeny
  • Sequence Alignment
  • Substrate Specificity
  • Temperature

Substances

  • Metals
  • Esterases
  • Lipase

Grants and funding

This work was financed by the Scientific and Technological Research Council (MINECO, Spain), grants CTQ2014-59632-R, CTQ2013-48995-C2-2-R and AC2015-00008-00-00, by the Pla de Recerca de Catalunya, grants 2009SGR-819 and 2014SGR-534 00327, by PCI-AECID project A203563511, and by the Generalitat de Catalunya to the “Xarxa de Referència en Biotecnologia” (XRB).