Carbohydrates in Chemistry and Biology || Sialidases

✍ Scribed by Ernst, Beat; Hart, Gerald W.; Sina, Pierre

• Publisher: Wiley-VCH Verlag GmbH
• Year: 2000
• Tongue: German
• Weight: 1021 KB
• Edition: 1
• Category: Article
• ISBN: 3527295119
• DOI: 10.1002/9783527618255.ch68

✦ Synopsis

Sialidases, also known as neuraminidases, catalyze the removal of terminal sialic acids from a variety of glycoconjugates. In animals, sialic acids are involved in a number of functions related to cell adhesion and cell survival and also the modulation of many cellular processes. The ubiquity and unique terminal position of sialic acids in sugars has provided a range of pathogens with a binding site for cell invasion. In addition, many bacteria have acquired the ability to utilize sialic acid as a carbon and energy source. Bacteria do not synthesize sialic acids, they are a recent invention of nature found in higher organisms, suggesting that those primitive pathogens which have sialidases acquired the genes by horizontal gene transfer. The key role of the enzyme in pathogenesis has made sialidases good targets for structure-based drug design. In this Chapter, we make a comparative study of the three dimensional structures of sialidases from viruses and bacteria. This shows that, despite very low sequence identity, all sialidases share a catalytic domain of the propeller structure first observed in the influenza virus neuraminidase. In many cases however, the enzymes possess additional domains that appear to have sugarbinding functions, suggesting that sialidases have evolved to be exquisitely adapted to their operating environment.