Dinucleotide-binding protein of ABC transporter family (U3GBP)

The Dinucleotide-binding protein of the ABC transporter family, specifically exemplified by the U3G-binding protein (U3GBP), is a specialized substrate-binding protein (SBP) primarily identified in bacteria such as Thermus thermophilus. It is the first identified member of the SBP subcluster D-I capable of binding dinucleotides, such as uridylyl-3'-5'-phospho-guanosine (U3G), which it delivers to ABC transporters for cellular uptake (Chandravanshi et al., 2021). The protein functions via a characteristic Venus Fly-trap conformational change upon ligand binding, a mechanism common among periplasmic binding proteins. Interestingly, it also demonstrates moonlighting activity by binding phospholipid precursors like sn-glycerophosphocholine (GPC) at a secondary site, indicating a role in membrane metabolism. While primarily a subject of basic microbiological research, its role in bacterial nutrient acquisition and signaling makes it a potential focal point for developing novel antibacterial strategies or biosensors for dinucleotides.

Other names

U3G-binding proteinUridylyl-3'-5'-phospho-guanosine-binding proteinSubstrate-binding protein of subcluster D-IUgpB-like protein

The protein utilizes a Venus Fly-trap mechanism to capture dinucleotide substrates (such as U3G) in the periplasm and deliver them to the transmembrane domains of an ABC transporter for translocation into the cytoplasm.