A Peptide-Induced Self-Cleavage Reaction Initiates the Activation of Tyrosinase.
Kampatsikas, I., Bijelic, A., Pretzler, M., Rompel, A.(2019) Angew Chem Int Ed Engl 58: 7475-7479
- PubMed: 30825403 
- DOI: https://doi.org/10.1002/anie.201901332
- Primary Citation of Related Structures:  
6ELS, 6ELT, 6ELV - PubMed Abstract: 
The conversion of inactive pro-polyphenol oxidases (pro-PPOs) into the active enzyme results from the proteolytic cleavage of its C-terminal domain. Herein, a peptide-mediated cleavage process that activates pro-MdPPO1 (Malus domestica) is reported. Mass spectrometry, mutagenesis studies, and X-ray crystal-structure analysis of pro-MdPPO1 (1.35 Å) and two separated C-terminal domains, one obtained upon self-cleavage of pro-MdPPO1 and the other one produced independently, were applied to study the observed self-cleavage. The sequence Lys 355-Val 370 located in the linker between the active and the C-terminal domain is indispensable for the self-cleavage. Partial introduction (Lys 352-Ala 360) of this peptide into the sequence of two other PPOs, MdPPO2 and aurone synthase (CgAUS1), triggered self-cleavage in the resulting mutants. This is the first experimental proof of a self-cleavage-inducing peptide in PPOs, unveiling a new mode of activation for this enzyme class that is independent of any external protease.
Organizational Affiliation: 
Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstraße 14, 1090, Wien, Austria.