pfam10585: UBA_e1_thiolCys (this model, PSSM-Id:313744 is obsolete and has been replaced by 463157)
Ubiquitin-activating enzyme active site
Ubiquitin-activating enzyme (E1 enzyme) activates ubiquitin by first adenylating with ATP its C-terminal glycine residue and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding an ubiquitin-E1 thiolester and free AMP. Later the ubiquitin moiety is transferred to a cysteine residue on one of the many forms of ubiquitin-conjugating enzymes (E2). This domain carries the last of five conserved cysteines that is part of the active site of the enzyme, responsible for ubiquitin thiolester complex formation, the active site being represented by the sequence motif PICTLKNFP.
Jiyao W et al.(2023). "The conserved domain database in 2023.",