DNA aptamers targeting this protein were used in the original version of FluMag-SELEX. This protein is tagged with a fluorophore and added to each MHC monomer in an MHC tetramer assay. Labeled DNA fragments (-5[1])are passed through beads containing this protein in the enrichment step of BLESS sequencing for double-strand DNA damage. It’s not histidine, but a synthetic eight-amino-acid peptide targeting a variant of this protein is used in a version of (*) affinity chromatography in which it is tagged to recombinant proteins. Tryptophan residues line this protein’s binding pocket, which contains two shells of hydrogen bonding sites with its main ligand. This compound is frequently conjugated to horseradish peroxidase (-5[1])for use in western blots and ELISAs (“ee-LIE-zuhs”). For (-5[1])10 points, name this protein used throughout molecular biology for its extremely high affinity for biotin. (10[1])■END■ (10[10]0[6])