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

• DOI: 10.1371/journal.pone.0181029
• Publication Date: 2017-07-25T17:43:28Z
• Authors: Judit Ribera; Mónica Estupiñán; Alba Fuentes; Amanda Fillat; Josefina Martínez; Pilar Diaz
• Keywords: Mesophile; Esterase; Extremophile; Bacillus (shape); Thermostability; Geobacillus stearothermophilus; Eubacterium; Strain (injury); Extreme environment

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