An extracellular protease containing a novel C-terminal extension produced by a marine-originated haloarchaeon

Marine microorganisms have long been acknowledged as a significant reservoir of enzymes required for industrial use. In this study, novel extracellular protease Hsl HlyB derived from marine-originated haloarchaeon Halostella pelagica DL-M4 T was identified. contained polycystic kidney disease (PKD) domain and pre-peptidase C-terminal (PPC) at the C-terminus. Truncation replacement extension (CTE) demonstrated importance CTE in maintaining activity secreted by haloarchaeon. HlyBΔCTE were expressed Escherichia coli BL21(DE3), purified high-affinity column refolding gel filtration chromatography. The molecular masses 42 kDa 20 kDa, respectively. optimum catalytic reaction conditions 50°C, pH 8.5, NaCl 3.5 M 7.5, 3 M, They showed good stability hydrolysis capabilities towards wide range protein substrates. higher rate better thermal than wild type against azocasein tetrapeptide substrate. hydrolysates soybean hydrolyzed had smaller average shorter peptide chain lengths those HlyB. These results indicated diversity halolysins haloarchaea to harness organic nitrogen marine environment provided promising candidates application various industries.