Central protein that confers the ability to take up biotin on E.coli; while biotin transport requires BioM at very low (pM) concentrations at higher (nM) concentrations expression of BioY alone suffices for uptake. Part of a biotin transporter holocomplex composed of BioM, BioN and BioY. BioMN complexes can also be readily purified, but not BioMY nor BioNY complexes. BioY homodimers are also seen. Only the BioMNY complex has ATPase activity. Belongs to the BioY family.