In the N-end rule pathway, the N-terminal residue of a protein is recognized by specific E3 ligases that promote its ubiquitination and proteasomal degradation. Now the structural basis for the recognition of N-terminal basic residues by the UBR box from yeast Ubr1 is solved. Together with functional analysis, the work reveals that the residue at position 2 of the substrate may influence the binding.
- Woo Suk Choi
- Byung-Cheon Jeong
- Hyun Kyu Song