The crystal structure of the saccharide-free form of the basic form of winged-bean agglutinin (WBAI) has been solved by the molecular-replacement method and refined at 2.3 A resolution. The final R factor is 19.7% for all data in the resolution range 8.0-2 ...
The crystal structure of the saccharide-free form of the basic form of winged-bean agglutinin (WBAI) has been solved by the molecular-replacement method and refined at 2.3 A resolution. The final R factor is 19.7% for all data in the resolution range 8.0-2.3 A. The asymmetric unit contains two half-dimers, each located on a crystallographic twofold axis. The structure of the saccharide-free form is compared with that of the complex of WBAI with methyl-alpha-D-galactoside. The complex is composed of two dimers in the asymmetric unit. The intersubunit interactions in the dimer are nearly identical in the two structures. The binding site of the saccharide-free structure contains three ordered water molecules at positions similar to those of the hydroxyl groups of the carbohydrate which are hydrogen bonded to the protein. Superposition of the saccharide-binding sites of the two structures shows that the major changes involve expulsion of these ordered water molecules and a shift of about 0.6 A of the main-chain atoms of the variable loop.
Related Citations:
Carbohydrate Specificity and Quaternary Association in Basic Winged Bean Lectin: X-Ray Analysis of the Lectin at 2.5 A Resolution Prabu, M.M., Sankaranarayanan, R., Puri, K.D., Sharma, V., Surolia, A., Vijayan, M., Suguna, K. (1998) J Mol Biol 276: 787
Crystallization and Preliminary X-Ray Studies of the Basic Lectin from Winged Bean (Psophocarpus Tetragonolobus) Sankaranarayanan, R., Puri, K.D., Ganesh, V., Banerjee, R., Surolia, A., Vijayan, M. (1993) J Mol Biol 229: 558
Organizational Affiliation:
Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560 012, India.
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