NbVHH05 is a 111 residue single-domain antibody fragment that binds the VHH05-tag epitope. NbVHH05 was derived from a heavy chain antibody originally isolated from an alpaca immunized with a purified recombinant fragment (residues 1-234) of Homo sapiens UBE2J1 (HGNC:17598) (PMID:31518855).