Trans-sialidase-like sequences from Trypanosoma congolense conserve most of the critical active site residues found in other trans-sialidases.
Trypanosoma congolense is the agent of Nagana, the trypanosomiasis in African ruminants. Trypanosomes express an enzyme called trans-sialidase, which is believed to play an important role in maintaining pathogenicity of the parasites. Thus far, only two complete trans-sialidase sequences have been characterised, one from the American trypanosome T. cruzi and one from the African trypanosome T. brucei brucei. Although the crystal structure of T. cruzi trans-sialidase has recently been published [Buschiazzo et al., Mol. Cell 10 (2002), pp. 757-768], a number of questions concerning the exact transfer mechanism remain unanswered. The availability of further trans-sialidase sequences will ensure a better understanding of how transfer activity can be achieved and will provide the opportunity to develop highly specific, structure-based trans-sialidase inhibitors. Utilising a PCR-based approach two different trans-sialidase gene copies from T. congolense were identified, which share only 50% identity with each other, but show significant similarity with known viral, bacterial and trypanosomal sialidases and trans-sialidases. In both partial sequences most of the critical active site residues common to other trypanosomal sialidases and trans-sialidases are conserved. This is further illustrated by modelling the active site of the longer of the two partial gene sequences.
Tiralongo
Evelin
E
Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
Martensen
Ilka
I
Grötzinger
Joachim
J
Tiralongo
Joe
J
Schauer
Roland
R
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D017931:DNA Primers; D006023:Glycoproteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000201:enzymology; D014348:Trypanosoma congolense / Q000201:enzymology* / Q000235:genetics; D014349:Trypanosoma cruzi / Q000201:enzymology
D017931:DNA Primers; D006023:Glycoproteins; C069715:trans-sialidase; D009439:Neuraminidase