Increasing the thermal stability of euphauserase

• Published in: European Journal of Biochemistry
• Main Authors: Benjamin, David C., Kristjánsdóttir, Sigrídur, Gudmundsdóttir, Ágústa
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Antarctic; Antarc*; Antarctic Krill
• Online Access: http://dx.doi.org/10.1046/j.1432-1327.2001.01857.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1432-1327.2001.01857.x; https://febs.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1432-1327.2001.01857.x

A molecular model of Antarctic krill euphauserase based on the known crystal structure of its fiddler crab analog, collagenase I, indicates that the core structure of these enzymes is almost identical. Euphauserase is a cold‐active and thermally sensitive enzyme with a high affinity for Lys, Arg and large hydrophobic amino acids. Residue Phe137 in euphauserase, localized in loop D (autolysis loop), is highly exposed on the surface of the molecule. Therefore, it appeared to be an easy target for autolysis. The broadly specific euphauserase has a low affinity for negatively charged residues. In order to increase the stability of the enzyme, two mutants were created in which residue Phe137 was replaced by a Glu and an Asp residue. Both mutations resulted in increased stability of the recombinant euphauserase towards thermal inactivation.