Entamoeba invadens: Cloning and molecular characterization of chitinases

• Published in: Experimental parasitology 2009-11, Vol.123 (3), p.244-249
• Main Authors: Dey, Tuli, Basu, Raunak, Ghosh, Sudip K
• Format: Article
• Language: English
• Subjects: Amebiasis; Amino Acid Sequence; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Chitin - metabolism; Chitinase; Chitinases - chemistry; Chitinases - genetics; Chitinases - metabolism; Chromatography, Affinity; Chromatography, High Pressure Liquid; Cloning, Molecular; E. histolytica; E. invadens; Electrophoresis, Polyacrylamide Gel; Entamoeba - enzymology; Entamoeba - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; General aspects. Techniques; Homology modeling; Life cycle. Host-agent relationship. Pathogenesis; Methods and techniques (sampling, tagging, trapping, modelling...); Microspheres; Models, Molecular; Molecular Sequence Data; Protein Structure, Tertiary; Protozoa; Recombinant Proteins - metabolism; Sequence Alignment; Substrate Specificity
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2009.07.008

Entamoeba histolytica, the causative agent of amebiasis infects through its cyst form and this transmission may be blocked using encystation specific protein as drug target. In this study, we have characterized the enzyme chitinase which express specifically during encystation. The reptilian parasite Entamoeba invadens, used as a model for encystation study contain three chitinases. We report the molecular cloning, over-expression and biochemical characterization of all three E. invadens chitinase. Cloned chitinases were over-expressed in bacterial system and purified by affinity chromatography. Their enzymatic profiles and substrate cleaving patterns were characterized. All of them showed binding affinity towards insoluble chitin though two of them lack the chitin binding domain. All the chitinases cleaved and released dimmers from the insoluble substrate and act as an exochitinase. Homology modeling was also done to understand the substrate binding and cleavage pattern.