Papain-like cysteine proteinase zone (PCP-zone) and PCP structural catalytic core (PCP-SCC) of enzymes with cysteine proteinase fold

Konstantin Denessiouk, Vladimir N. Uversky, Sergei E. Permyakov, Eugene A. Permyakov, Mark S. Johnson, Alexander I. Denesyuk

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5 Citations (Scopus)
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There are several families of cysteine proteinases with different folds - for example the (chymo)trypsin fold family and papain-like fold family - but in both families the hydrolase activity of cysteine proteinases requires a cysteine residue as the catalytic nucleophile. In this work, we have analyzed the topology of the active site regions in 146 three-dimensional structures of proteins belonging to the Papain-like Cysteine Proteinase (PCP) superfamily, which includes papain as a typical representative of this protein superfamily. All analyzed enzymes contain a unique structurally closed conformation - a "PCP-Zone" - which can be divided into two groups, Class A and Class B. Eight structurally conserved amino acids of the PCP-Zone form a common Structural Core. The Structural Core, catalytic nucleophile, catalytic base and residue Xaa - which stabilizes the side-chain conformation of the catalytic base - make up a PCP Structural Catalytic Core (PCP-SCC). The PCP-SCC of Class A and Class B are divided into 5 and 2 types, respectively. Seven variants of the mutual arrangement of the amino-acid side chains of the catalytic triad - nucleophile, base and residue Xaa - within the same fold clearly demonstrate how enzymes with the papain-like fold adapt to the need to perform diverse functions in spite of their limited structural diversity. The roles of both the PCP-Zone of SARS-CoV-2-PLpro described in this study and the NBCZone of SARS-CoV-2-3CLpro presented in our earlier article (Denesyuk AI, Johnson MS, Salo-Ahen OMH, Uversky VN, Denessiouk K. Int J Biol Macromol. 2020;153:399-411) that are in contacts with inhibitors are discussed.
Original languageEnglish
Pages (from-to)1438-1446
JournalInternational Journal of Biological Macromolecules
Publication statusPublished - 2020
MoE publication typeA1 Journal article-refereed


  • COVID-19
  • Catalytic triad
  • Cysteine proteinases
  • SARC-CoV-2
  • InFlames


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