Directed mutagenesis of the Trypanosoma cruzi trans-sialidase enzyme identifies two domains involved in its sialyltransferase activity.
Of the increasing number of sialidases found to be made by microorganisms, the trypanosome trans-sialidase is unique in its added ability to efficiently carry out a sialyltransferase reaction using preformed glycoconjugates. The enzyme is predicted to have a multidomain structure, with one domain containing sequence and expected structural features found in bacterial sialidases. The trans-sialidase is very similar in overall sequence to another trypanosome enzyme that has only sialidase activity. Hybrid expression constructs containing pieces of these trypanosome trans-sialidase and sialidase genes were used to determine which regions of trans-sialidase are required for sialyltransferase activity. Two domains were found to influence the enzymatic activity: the N-terminal catalytic domain, and a downstream domain that resembles an Fn3-like module.
Smith
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LE
Department of Pathology, New York University School of Medicine, NY 10010, USA.
Eichinger
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D005690:Galactose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008847:Micromonospora / Q000201:enzymology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009439:Neuraminidase / Q000737:chemistry* / Q000235:genetics*; D016366:Open Reading Frames; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012799:Sialyltransferases / Q000378:metabolism; D013329:Structure-Activity Relationship; D014349:Trypanosoma cruzi / Q000201:enzymology*
D012799:Sialyltransferases; D009439:Neuraminidase; D005690:Galactose