Helper-component proteinase (, ''HC-Pro'') is an enzyme. This enzyme catalyses the following chemical reaction : Hydrolyses a Gly-Gly bond at its own

C-terminus The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...

, commonly in the sequence -Tyr-Xaa-Val-Gly-Gly, in the processing of the potyviral polyprotein This enzyme is present in plant RNA viruses of the '' Potyviridae'' family. HC-Pro is encoded by all

potyvirus ''Potyvirus'' is a genus of positive-strand RNA viruses in the family ''Potyviridae''. Plants serve as natural hosts. The genus is named after member virus ''potato virus Y''. Potyviruses account for about thirty percent of the currently known p ...

es, but is absent in some members of the ''

Ipomovirus ''Ipomovirus'' is a genus of positive-strand RNA viruses in the family '' Potyviridae''. Member viruses infect plants and are transmitted by whiteflies ('' Bemisia tabaci''). The name of the genus is derived from '' Ipomoea'' – the generic na ...

'' genus. HC-Pro is involved in virus transmission, virus polyprotein processing, and suppression of RNA silencing, an antiviral mechanism of plants.

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External links

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