Sialidase primary structures

FIGURE 8. Schematic survey of an alignment of 12 sialidase primary structures and the location of 16 conserved amino acids. 

FIGURE 9. Dendrogram of similarities among sialidase primary structures based on identical amino acids. 

In the first primary structures of microbial sialidases, obtained by cloning and sequencing of the respective genes from Clostridium perfringens [769], Vibrio cholerae [770], Clostridium sordellii [77 ] and Salmonella typhimurium [772], an amino acid sequence motif was detected, which is repeated four-fold in each protein S-X-D-X-G-X-T-W [773]. This motif, named the Asp-box, was found in all 16 sialidases of animals, trypanosomes, and bacteria, which have so far been sequenced (see refs. [660,768] and Table 18). In viral sialidases, however, the motif was rarely detectable (e.g. only the sialidase from N9 influenza A virus strain exhibits the complete motif [786] and has probably undergone mutational alterations). 

Traving, C., Schauer, R., and Roggentin, P., 1993, The primary structure of the large sialidase isoenzyme of Clostridium perfringens A99 and its comparison with further sialidases, Gly-coconj. J. 10 238-239. 

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