A novel, extremely alkaliphilic and cold-active esterase from Antarctic desert soil

作者：Hu Xiao Ping; Heath Caroline; Taylor Mark Paul; Tuffin Marla; Cowan Don^*

来源：Extremophiles, 2012, 16(1): 79-86.

DOI：10.1007/s00792-011-0407-y

• Metagenomic
• Esterase
• Cold active
• Psychrophilic
• Alkaliphilic

A novel, cold-active and highly alkaliphilic esterase was isolated from an Antarctic desert soil metagenomic library by functional screening. The 1,044 bp gene sequence contained several conserved regions common to lipases/esterases, but lacked clear classification based on sequence analysis alone. Moderate (< 40%) amino acid sequence similarity to known esterases was apparent (the closest neighbour being a hypothetical protein from Chitinophaga pinensis), despite phylogenetic distance to many of the lipolytic "families". The enzyme functionally demonstrated activity towards shorter chain p-nitrophenyl esters with the optimal activity recorded towards p-nitrophenyl propionate (C3). The enzyme possessed an apparent T(opt) at 20A degrees C and a pH optimum at pH 11. Esterases possessing such extreme alkaliphily are rare and so this enzyme represents an intriguing novel locus in protein sequence space. A metagenomic approach has been shown, in this case, to yield an enzyme with quite different sequential/structural properties to known lipases. It serves as an excellent candidate for analysis of the molecular mechanisms responsible for both cold and alkaline activity and novel structure-function relationships of esterase activity.

• 出版日期2012-1