Allose-binding protein (AlsB) (AlsB)

The Allose-binding protein (AlsB) is a periplasmic substrate-binding protein found in Escherichia coli (UniProt P0AE52). It serves as the primary receptor for the AlsABC ATP-binding cassette (ABC) transporter system, which facilitates the uptake of the rare hexose sugar D-allose (Kim et al., 1997). Structurally, AlsB consists of two lobes that close around the substrate in a Venus flytrap mechanism upon binding. Once the sugar is bound, AlsB interacts with the membrane-bound components AlsA and AlsC to trigger ATP hydrolysis and transport the sugar into the cytoplasm (EcoCyc). Although D-allose is not a common carbon source, the Als system allows E. coli to utilize it under specific environmental conditions. From a therapeutic perspective, AlsB is not a target for any currently approved drugs, but it is frequently studied in the context of bacterial physiology and protein engineering. Its high affinity and specificity for D-allose make it a candidate for the development of biosensors and ligand-binding assays. In the broader scope of antimicrobial research, targeting nutrient transporters like AlsB could theoretically inhibit bacterial growth, though such strategies are not yet clinically realized.

Other names

D-allose-binding periplasmic proteinAlsBD-allose-binding protein

Substrate-binding protein that captures D-allose in the periplasm and delivers it to the AlsAC membrane complex for ATP-dependent transport into the cell (UniProt P0AE52).