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Identification and Characterization of Activating and Conjugating Enzymes of the Ubiquitin System from the Unicellular Alga Chiamydomonas reinhardtii
Author(s) -
Schunn G.,
Kampen J.,
NieIänder U.,
Wettern M.
Publication year - 1999
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.1999.tb00713.x
Subject(s) - ubiquitin , ubiquitin conjugating enzyme , enzyme , biology , biochemistry , ubiquitins , ubiquitin ligase , deubiquitinating enzyme , gene
Using a biochemical approach we identified families of ubiquitin‐activating and ubiquitin‐conjugating enzymes in Chiamydomonas reinhardtii . The family of ubiquitin‐activating enzymes, characterized by their ability to form thioesters with ubiquitin and eluting off a ubiquitin affinity column by ATP‐depletion probably consists of at least four members. Whereas one of these enzymes is active under a broad range of pH values, thioesterof the other UBAs with ubiquitin is restricted to pH 7.5. Two ubiquitin‐activating enzymes are metabolically phosphory‐lated which is assumed to be an activity control mechanism. Most of the 7 ubiquitin‐conjugating enzymes detected in this study were found to bind rather tightly to an anion exchange column, and eluted off the column at specific salt concentra tions. Two of the ubiquitin‐conjugating enzymes described here did, however, not bind to this column. These enzymes can, as all other C. reinhardtii ubiquitin‐conjugating enzymes, perform thioester formation with ubiquitin regardless of the source (plant/animal) of the ubiquitin‐activating enzyme.