GDP-Man

Guanosine 5′-diphospho-α-D-mannose (GDP-mannose) is a nucleotide sugar, which serves as a key donor of mannose residues in various glycosylation processes. It plays an important role in the biosynthesis of glycoproteins, glycolipids, and polysaccharides, particularly in organisms ranging from bacteria to humans.

Structure & Properties:

• Molecular Weight (MW): Approximately 566-610 g/mol (varies slightly depending on hydration and salt form).
• Chemical Formula: C16H23N5Na2O16P2 (common estimate for the disodium salt form).
• Synonyms: GDP-mannose disodium salt, Guanosine diphosphate mannose disodium salt
• CAS Number: 60259-80-5

Biological Role:

• Biosynthesis Pathway: GDP-α-D-mannose is synthesized from mannose-6-phosphate via a two-step enzymatic process. It is critical in mannose metabolism and acts as a substrate for several glycosyltransferases involved in the biosynthesis of mannose-containing glycans.
• Function: GDP-mannose is used by glycosyltransferases to transfer mannose to growing carbohydrate chains during the synthesis of glycoproteins, glycolipids, and polysaccharides. It is also essential for the formation of glycosaminoglycans and other structural polysaccharides in organisms.

Applications:

1. Glycosylation Studies: Used to study the enzymatic processes involved in adding mannose to glycoconjugates, such as glycoproteins and glycolipids.
2. Enzyme Assays: Serves as a substrate in glycosyltransferase assays to investigate the role of mannose in glycan biosynthesis.
3. Polysaccharide Synthesis: Important in the synthesis of mannose-rich polysaccharides, such as those found in bacterial and plant cell walls.

Key Roles:

• Protein Glycosylation: GDP-mannose is crucial for the N-linked glycosylation of proteins, which involves the attachment of mannose residues to specific amino acids on proteins in the endoplasmic reticulum.
• Polysaccharide Formation: It is essential in the production of mannose-rich polysaccharides like hemicelluloses in plants and capsular polysaccharides in bacteria.
• Metabolic Pathways: GDP-mannose is an intermediate in the synthesis of ascorbic acid (vitamin C) in plants and some other organisms.

Storage and Stability:

• Storage: Store at -20°C in a dry, sealed container to prevent moisture absorption and degradation.
• Stability: It is stable under these storage conditions but should be protected from light and moisture.

Significance in Research:

1. Mannose Metabolism: GDP-α-D-mannose plays a significant role in studying disorders of mannose metabolism, such as Congenital Disorders of Glycosylation (CDGs), where defects in glycosylation can lead to a variety of developmental and metabolic issues.
2. Bacterial Glycobiology: It is important in the study of bacterial capsule formation, which is essential for pathogenic bacteria to evade the immune system.

Research Applications:

• Drug Development: The role of GDP-mannose in glycosylation makes it a potential target for therapeutic interventions in diseases caused by glycosylation defects.
• Plant Biology: GDP-mannose is studied for its role in the biosynthesis of plant cell wall components, such as cellulose and hemicellulose.
• Vaccine Development: Its role in capsular polysaccharide biosynthesis makes it relevant in vaccine research for encapsulated bacteria like Streptococcus pneumoniae.

This compound is fundamental in glycosylation research, with applications across microbiology, plant biology, and disease studies related to glycosylation disorders.