ubiquitin-like (Ubl) domain found in ubiquitin-like protein 3 (UBL3) and similar proteins
UBL3, also termed membrane-anchored ubiquitin-fold protein (MUB), or protein HCG-1, belongs to a newly described MUB protein family with structural homology with ubiquitin. MUB proteins have a beta-grasp ubiquitin-like (Ubl) domain with longer N- and C-termini and extended loops. The Ubl domain contains a C-terminal CAAX-box, a canonical motif for protein prenylation, which is modified through protein lipidation with a hydrophobic membrane anchor. The lipidation and membrane localization inhibit attachment of MUBs to target proteins.
Comment:3 (K11, K48/R,K63K, Ub numbering) of the 7 lysines involved in chain linkage in ubiquitin (K6, K11, K27, K29, K33, K48, or K63, Ub numbering) are conserved in this family, K27 a lysine highly conserved in the Ubl_ubiquitin_like family is not conserved in this subfamily, for most in this subfamily the residue corresponding to K6 is a conserved Ile, for K33 is a conserved Asn; may have roles other than chain linkage
Jiyao W et al.(2023). "The conserved domain database in 2023.",