This is the C-terminal domain of the 26S proteasome regulatory subunit RPN5 proteins.This helical domain can be found adjacent to Pfam:PF01399. The 26S proteasome is the major ATP-dependent protease in eukaryotes. Three subcomplexes form this degradation machine: the lid, the base, and the core. The helices found at the C terminus of each lid subunit form a helical bundle that directs the ordered self-assembly of the lid subcomplex. This domain which comprises the tail of RPN5 along with the tail of Rpn9, are important for Rpn12 binding to the lid [1].

1: Formation of an intricate helical bundle dictates the assembly of the 26S proteasome lid. Estrin E, Lopez-Blanco JR, Chacon P, Martin A; Structure. 2013;21:1624-1635. PMID:23911091

2: Deep classification of a large cryo-EM dataset defines the conformational landscape of the 26S proteasome. Unverdorben P, Beck F, Sledz P, Schweitzer A, Pfeifer G, Plitzko JM, Baumeister W, Forster F; Proc Natl Acad Sci U S A. 2014;111:5544-5549. PMID:24706844