Journal Article

A novel halolysin without C-terminal extension from an extremely halophilic archaeon

Cui, Heng-Lin, Hou, Jing, Li, Si-Ya, Zhao, Yang-Jie

2022

Overview

Halolysins are extracellular proteases secreted by halophilic archaea for nutritional purposes. They bear great application potentials in various industries. Yet the diversity of halolysins remains underexplored. In this study, a halolysin from the extremely halophilic archaeon Haladaptatus sp. DYF46 (Hly Hap ) was identified to be a novel type of halolysin without C-terminal extension (CTE). Addition of the CTE of a halolysin from Halococcus salifodinae to Hly Hap did not significantly affect its extracellular proteolytic activity. Mature Hly Hap was generated from recombinant Hly Hap precursor by high-affinity column refolding. Hly Hap displayed optimal activity at 0.25-0.50 M NaCl, 45 °C and pH 8.5-9.0. Interestingly, Hly Hap preferred a low salinity and was stable in a broad range of salinity, albeit from an extremely halophilic archaeon. Ca 2+ and Mg 2+ significantly promoted Hly Hap activity. Hly Hap activity was stable with organic solvents and detergents. The K m and V max values of Hly Hap against azocasein were 0.018 mM and 7,179 U/mg, and those against succinyl-Ala-Ala-Pro-Phe-pNA were 0.32 mM and 3×10 6 μmol/min/μg, respectively. The unusual traits of Hly Hap , a novel type of halolysin without CTE, may endow it with strong potential for various industrial uses, such as biocatalysis in fluctuating salinities and aqueous-organic solvent. Key points • This is the first report of a novel type of halolysin without C-terminal extension • Hly Hap was obtained by heterologous expression and high-affinity column refolding • Hly Hap exhibited good salinity tolerance

• Publisher: Springer Berlin Heidelberg,Springer,Springer Nature B.V
• Subject: Affinity / Analysis / Archaea / Archaeabacteria / Azocasein / biocatalysis / Biomedical and Life Sciences / Biotechnologically Relevant Enzymes and Proteins / Biotechnology / calcium / Calcium ions / Catalysis / Detergents / Halophilic archaea / heterologous gene expression / Identification and classification / Industrial applications / Life Sciences / Magnesium / Microbial Genetics and Genomics / Microbiology / Organic solvents / Peptide Hydrolases - metabolism / Properties / Proteases / proteinases / Proteolysis / Salinity / Salinity effects / Salinity tolerance / Salt Tolerance / Serine Endopeptidases - metabolism / Sodium chloride / Sodium Chloride - metabolism / Solvents / Structure