The 20S as a stand-alone proteasome in cells can degrade the ubiquitin tag
Indrajit Sahu, Sachitanand M Mali, Prasad Sulkshane, Cong Xu, Andrey Rozenberg, Roni Morag, Manisha Priyadarsini Sahoo, Sumeet K Singh, Zhanyu Ding, Yifan Wang, Sharleen Day, Yao Cong, Oded Kleifeld, Ashraf Brik, Michael H Glickman