Sialidases from gut bacteria: a mini-review

Area of Science:

• Microbiology
• Enzymology
• Glycobiology

Background:

• Sialidases are enzymes that cleave terminal sialic acids from carbohydrates on glycoproteins and glycolipids.
• In the gastrointestinal tract, sialic acids are abundant in mucins, serving as a nutrient source for many bacteria.
• Bacterial sialidases exhibit diverse substrate specificities and reaction mechanisms, impacting host-microbe interactions.

Purpose of the Study:

• To review the structural and biochemical properties of bacterial sialidases.
• To explore the role of sialidases in the interaction between gut bacteria and epithelial surfaces.
• To highlight the different classes of sialidases, including hydrolytic and intramolecular trans-sialidases (IT-sialidases).

Main Methods:

• Literature review of existing research on bacterial sialidases.
• Analysis of substrate specificity and enzymatic reactions of different sialidase classes.
• Examination of structural and biochemical data for sialidases from gut microbiota.

Main Results:

• Sialidases are crucial for bacteria to utilize sialic acids from host mucins.
• Hydrolytic sialidases generally display broad substrate specificity (α2,3-, α2,6-, α2,8-linkages).
• Intramolecular trans-sialidases (IT-sialidases) are a distinct class, often specific for α2,3-linked sialic acids, releasing 2,7-anhydro-N-acetylneuraminic acid.

Conclusions:

• Bacterial sialidases play a significant role in nutrient acquisition and host-microbe dynamics within the gut.
• Understanding the diversity and specificity of sialidases is key to deciphering their impact on gastrointestinal health and disease.
• Further research into IT-sialidases may reveal novel mechanisms of bacterial adaptation and interaction.