3F53

Crystal structure of Toxoplasma gondii micronemal protein 1 bound to 2F-3'SiaLacNAc

Summary for 3F53

• Entry DOI: 10.2210/pdb3f53/pdb
• Related: 2JH1 2JH7 2JHD 3F5A 3F5E
• Descriptor: Micronemal protein 1, N-acetyl-alpha-neuraminic acid-(2-3)-2-deoxy-2-fluoro-beta-D-galactopyranose, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: cell adhesion, micronemal protein, carbohydrate, fluorine, toxoplasma gondii, cytoplasmic vesicle, lectin, virulence
• Biological source: Toxoplasma gondii
• Cellular location: Cytoplasmic vesicle, secretory vesicle, microneme: O00834
• Total number of polymer chains: 1
• Total formula weight: 28707.69

Authors

Garnett, J.A. (deposition date: 2008-11-03, release date: 2009-07-28, Last modification date: 2024-11-06)

Primary citation

Garnett, J.A.,Liu, Y.,Leon, E.,Allman, S.A.,Friedrich, N.,Saouros, S.,Curry, S.,Soldati-Favre, D.,Davis, B.G.,Feizi, T.,Matthews, S.
Detailed insights from microarray and crystallographic studies into carbohydrate recognition by microneme protein 1 (MIC1) of Toxoplasma gondii.
Protein Sci., 18:1935-1947, 2009

PubMed Abstract: The intracellular protozoan Toxoplasma gondii is among the most widespread parasites. The broad host cell range of the parasite can be explained by carbohydrate microarray screening analyses that have demonstrated the ability of the T. gondii adhesive protein, TgMIC1, to bind to a wide spectrum of sialyl oligosaccharide ligands. Here, we investigate by further microarray analyses in a dose-response format the differential binding of TgMIC1 to 2-3- and 2-6-linked sialyl carbohydrates. Interestingly, two novel synthetic fluorinated analogs of 3'SiaLacNAc(1-4) and 3'SiaLacNAc(1-3) were identified as highly potent ligands. To understand the structural basis of the carbohydrate binding specificity of TgMIC1, we have determined the crystal structures of TgMIC1 micronemal adhesive repeat (MAR)-region (TgMIC1-MARR) in complex with five sialyl-N-acetyllactosamine analogs. These crystal structures have revealed a specific, water-mediated hydrogen bond network that accounts for the preferential binding of TgMIC1-MARR to arrayed 2-3-linked sialyl oligosaccharides and the high potency of the fluorinated analogs. Furthermore, we provide strong evidence for the first observation of a C--F...H--O hydrogen bond within a lectin-carbohydrate complex. Finally, detailed comparison with other oligosaccharide-protein complexes in the Protein Data Bank (PDB) reveals a new family of sialic-acid binding sites from lectins in parasites, bacteria, and viruses.

PubMed: 19593815
DOI: 10.1002/pro.204

Experimental method

X-RAY DIFFRACTION (2 Å)