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Growth phase-dependent biosynthesis of Nep, a halolysin-like protease secreted by the alkaliphilic haloarchaeon Natrialba magadii

Authors :
R.E. De Castro
Roberto A. Paggi
Celeste Paola D’Alessandro
Enrique Alberto Madrid
Micaela Cerletti
Source :
Letters in Applied Microbiology.
Publication Year :
2010
Publisher :
Oxford University Press (OUP), 2010.

Abstract

Aims: The alkaliphilic haloarchaeon Natrialba magadii secretes a halolysin-like protease (Nep) that is active and stable in high salt and in organic solvents, which represents a potential resource for biocatalysis in low water activity conditions. In this study, the effect of the growth stage on Nep biosynthesis was examined. Methods and Results: Nep mRNA and extracellular protease activity were measured by RT-PCR and azocaseinolytic activity determination, respectively. Increased abundance in Nep mRNA was observed in Nab. magadii cells with culture age, which correlated with accumulation of extracellular protease activity. Moreover, a ‘stationary phase behavior’ on synthesis of Nep was evidenced in low-density cultures incubated with stationary phase medium. Conclusions: nep gene expression is up-regulated during the transition to the stationary phase in response to ‘factors’ (metabolite and/or regulatory molecule) occurring in high-density cultures of Nab. magadii. Although the identity of these molecules remains to be determined, preliminary evidence suggests that they are hydrophobic and stable in high salt and high pH values (3·5 mol l−1 NaCl, pH 10). Significance and impact of study: This study contributes to gain insight into the regulation of haloarchaeal protease biosynthesis, facilitating the large-scale production of this extremozyme for basic studies or potential applications.

Details

ISSN :
1472765X and 02668254
Database :
OpenAIRE
Journal :
Letters in Applied Microbiology
Accession number :
edsair.doi...........48c30a2606005792edb9f3bf7bda9236
Full Text :
https://doi.org/10.1111/j.1472-765x.2010.02855.x