You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
Generate a molecule that fulfills the requirement: The molecule is a proteasome inhibitor.
user
CCCC(=O)OCc1cc(CC(=O)NC(CCc2ccccc2)C(=O)NC2CCN(C(Cc3ccccc3)C(=O)NC(CC(C)C)C(=O)C3(C)CO3)C2=O)no1
assistant