GDPglucose

GDP-glucose is a nucleotide sugar that serves as a donor of glucose residues in certain glycosylation reactions. It consists of a guanosine diphosphate moiety linked to glucose via a pyrophosphate bridge, forming GDP-glucose. This compound functions as a substrate for specific glycosyltransferases that transfer glucose to growing polysaccharide chains, oligosaccharides, or glycoconjugates in various organisms.

Occurrence and roles are best described as organism-dependent. GDP-glucose is detected in a subset of bacteria, archaea, and some fungi where it participates in the biosynthesis of cell-surface glycans, capsule components, lipopolysaccharide structures, and exopolysaccharides. In these systems, GDP-glucose provides the glucose units that contribute to the structural diversity and protective functions of the glycans. In contrast, animals and many plants rely more prominently on UDP-glucose for similar glycosylation reactions, and GDP-glucose is generally less widespread in human biochemistry.

Biosynthesis typically involves GDP-glucose pyrophosphorylase, which catalyzes the reaction of GTP with glucose-1-phosphate to form GDP-glucose and inorganic pyrophosphate. The availability of GDP-glucose and activity of the corresponding glycosyltransferases influence the composition of the produced glycans. Research on GDP-glucose has focused on its enzymology, structural biology, and role in microbial cell wall biosynthesis, with interest in potential applications for antibiotic targets and the engineered production of glycoconjugates.

See also nucleotide sugars, UDP-glucose, GDP-mannose, glycosyltransferases.