Methods and compositions relating to E3 ring-E2 fusion proteins

摘要

Compositions are provided according to embodiments of the present invention which include an isolated fusion protein including an E3 protein RING motif bonded to an UCE E2 protein. In preferred embodiments, the C-terminus of the E3 protein RING motif is bonded to the N-terminus of the UCE E2 protein by an intervening peptide linker. Optionally, the peptide linker is 5-50 amino acids. Preferred is a peptide linker of 15-20 amino acids. Methods of identifying ubiquitylation modulators are provided according to embodiments of the present invention which include contacting an isolated fusion protein including an E3 protein RING motif bonded to an UCE E2 protein with a ubiquitylation substrate in the presence of a test substance. Ubiquitylation of the ubiquitylation substrate is then detected to determine the effect of the test substance on ubiquitylation of the ubiquitylation substrate.