![]() Structure and regulation of (pro-)legumain. Top-view on the AEP active site shows how Glu190 stabilizes the protonated state of Cys189 Sg.
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The cysteine protease legumain is a key player in immunity and cancer at different cellular locations, some of which are incompatible with its pH-stability. We solved the crystal structures of zymogenic and active legumain, unveiling its activation and regulation principles. Legumain contains an Asn-specific endopeptidase activity that is electrostatically released at acidic pH. Surprisingly, we uncovered a complementary proteolytic activation route, generating a carboxypeptidase activity. |
The context-dependent activation of legumain reconciles its partly conflicting moonlighting activities.
Mechanistic and structural studies on legumain explain its zymogenicity, distinct activation pathways, and regulation; Dall E. and Brandstetter H., Proc Natl Acad Sci USA 110, 27 (2013); doi: 10.1073/pnas.1300686110 |