The MetNIQ methionine transporter is member of the group of bacterial ATP-binding cassette (ABC) transporter complexes, and consists of the dimeric ATPase subunit MetN located at the cytoplasmic side of the plasma membrane and the dimeric transmembrane subunit MetI. MetQ is regarded as the periplasmic methionine-binding chaperon subunit. It is capable of transporting methionine from the periplasm into the cytoplasm in an ATP-dependent manner.