Bifidobacterium human milk oligosaccharide ABC transporter solute-binding protein (HMO-SBP)

Bifidobacterium human milk oligosaccharide ABC transporter solute-binding proteins are specialized extracellular receptors found in infant-associated bifidobacteria, such as Bifidobacterium longum subsp. infantis. These proteins are responsible for the high-affinity capture of complex glycans found in breast milk, known as human milk oligosaccharides (HMOs), which are otherwise indigestible by the host. By binding specific HMOs like 2'-fucosyllactose or lacto-N-tetraose, these proteins facilitate the transport of these prebiotics into the bacterial cell for fermentation. This mechanism provides a significant competitive advantage to beneficial bacteria, allowing them to dominate the neonatal gut microbiota and exclude potential pathogens. From a therapeutic perspective, these proteins are targets for synbiotic formulations where specific HMOs are provided as 'drugs' or supplements to promote the growth of beneficial strains. Their role is critical in establishing a healthy microbiome, modulating the immune system, and potentially reducing the risk of necrotizing enterocolitis and other inflammatory conditions in infants.

Other names

ABC transporter sugar-binding proteinSolute-binding protein (SBP)Extracellular solute-binding protein family 1Blon_0341 (2'-FL/3-FL binding protein)Blon_2171 (LNT/LNnT binding protein)Blon_0191 (Sialylated HMO binding protein)Bifidobacterial HMO transporter

These proteins act as the primary receptors for the capture and delivery of specific human milk oligosaccharides to the transmembrane permease components of ABC transporters, enabling the selective internalisation and subsequent metabolism of HMOs by beneficial Bifidobacteria.