Open AccessPropeptide dependent activation of the Antarctic krill euphauserase precursor produced in yeast
Author(s) -
Kristjánsdóttir Sigrídur,
Gudmundsdóttir Ágústa
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01273.x
Subject(s) - pichia pastoris , protein precursor , biochemistry , serine , trypsin , enzyme , isoelectric point , signal peptide , recombinant dna , antarctic krill , biology , yeast , amino acid , peptide sequence , chemistry , krill , gene , fishery
Euphauserase is a brachyurin type digestive enzyme isolated from Antarctic krill. The brachyurins belong to clan SA of the S1 family of serine endopeptidases. In this study, we demonstrate that the precursor form of recombinant euphauserase, termed pro‐r‐euphauserase, can be successfully expressed in Pichia pastoris . The presence of most of the 51‐residue euphauserase propeptide is essential during expression, under the growth conditions of Pichia . The propeptide may be required either for correct folding or processing of the enzyme. Cod trypsin generates a fully active r‐euphauserase from its precursor, which appears to be identical to the native enzyme. The mature r‐euphauserase sequence contains 250 amino‐acid residues including a 13‐residue activation peptide, which seems to be attached to the molecule by a disulfide bond. Euphauserase shares an average sequence identity of 62% with its type I brachyurin analogue, crab collagenase I. However, the identity between these two sequences is much higher in the regions shown to be important for the broad substrate specificity and collagen binding of crab collagenase I. The type I brachyurins share only 30–40% identities with the type II brachyurins and trypsins. The low isoelectric point of euphauserase, with a calculated pI value of 3.9, is typical for the type I brachyurins.