摘要:
Short heptapeptides were identified to function as ubiquitin (UB) mimics that are activated by El and form thioester conjugates with E1, E2, and HECT type E3 enzymes. The activities (k(cat)/K-1/2)of E1 with the UB-mimicking peptides are 130-1,400-fold higher than the equally long peptide with the native C-terminal sequence of UB. By forming covalent conjugates with E1, E2, and E3 enzymes, the UB-mimicking peptides can block the transfer of native UB through the cascade.