6FPC:
reference: Discovery of a new Pro-Pro endopeptidase, PPEP-2, provides mechanistic insights into the differences in substrate specificity within the PPEP family., Klychnikov OI, Shamorkina TM, Weeks SD, van Leeuwen HC, Corver J, Drijfhout JW, van Veelen PA, Sluchanko NN, Strelkov SV, Hensbergen PJ, J Biol Chem. 2018 May 23. pii: RA118.003244. doi: 10.1074/jbc.RA118.003244. PMID: 29794027

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