Download MendeleyStructural basis for the carbohydrate-specificity of basic winged-bean lectin and its differential affinity for Gal and GalNAc
Kulkarni, K.A., Katiyar, S., Surolia, A., Vijayan, M., Suguna, K.(2006) Acta Crystallogr D Biol Crystallogr 62: 1319-1324
- PubMed: 17057334
- DOI: https://doi.org/10.1107/S0907444906028198
- Primary Citation of Related Structures:
2DTW, 2DTY, 2DU0, 2DU1 - PubMed Abstract:
The crystal structure of the complexes of basic winged-bean lectin with galactose, 2-methoxygalactose, N-acetylgalactosamine and methyl-alpha-N-acetylgalactosamine have been determined. Lectin-sugar interactions involve four hydrogen bonds and a stacking interaction in all of the complexes. In addition, an N-H...O hydrogen bond involving the hydroxyl group at C2 exists in the galactose and 2-methoxygalactose complexes. An additional hydrophobic interaction involving the methyl group in the latter leads to the higher affinity of the methyl derivative. In the lectin-N-acetylgalactosamine complex the N-H...O hydrogen bond is lost, but a compensatory hydrogen bond is formed involving the O atom of the acetamido group. In addition, the CH(3) moiety of the acetamido group is involved in hydrophobic interactions. Consequently, the 2-methyl and acetamido derivatives of galactose have nearly the same affinity for the lectin. The methyl group alpha-linked to the galactose takes part in additional hydrophobic interactions. Therefore, methyl-alpha-N-acetylgalactosamine has a higher affinity than N-acetylgalactosamine for the lectin. The structures of basic winged-bean lectin-sugar complexes provide a framework for examining the relative affinity of galactose and galactosamine for the lectins that bind to them. The complexes also lead to a structural explanation for the blood-group specificity of basic winged-bean lectin.
Organizational Affiliation:
Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
