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Amino acid sequence of the winged bean (Psophocarpus tetragonolobus) basic lectin. Adenine binding and identification of the active-site tryptophan residue

Puri, KD and Surolia, Avadhesha (1994) Amino acid sequence of the winged bean (Psophocarpus tetragonolobus) basic lectin. Adenine binding and identification of the active-site tryptophan residue. In: Journal of Biological Chemistry, 269 (49). pp. 30917-30926.

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Official URL: http://www.jbc.org/content/269/49/30917.abstract

Abstract

The complete amino acid sequence of winged bean basic agglutinin (WBA I) was obtained by a combination of manual and gas-phase sequencing methods. Peptide fragments for sequence analyses were obtained by enzymatic cleavages using trypsin and Staphylococcus aureus V8 endoproteinase and by chemical cleavages using iodosobenzoic acid, hydroxylamine, and formic acid. COOH-terminal sequence analysis of WBA I and other peptides was performed using carboxypeptidase Y. The primary structure of WBA I was homologous to those of other legume lectins and more so to Erythrina corallodendron. Interestingly, the sequence shows remarkable identities in the regions involved in the association of the two monomers of E. corallodendron lectin. Other conserved regions are the double metal-binding site and residues contributing to the formation of the hydrophobic cavity and the carbohydrate-binding site. Chemical modification studies both in the presence and absence of N-acetylgalactosamine together with sequence analyses of tryptophan-containing tryptic peptides demonstrate that tryptophan 133 is involved in the binding of carbohydrate ligands by the lectin. The location of tryptophan 133 at the active center of WBA I for the first time subserves to explain a role for one of the most conserved residues in legume lectins.

Item Type: Journal Article
Publication: Journal of Biological Chemistry
Publisher: The American Society for Biochemistry and Molecular Biology.
Additional Information: Copyright of this article belongs to The American Society for Biochemistry and Molecular Biology.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 21 May 2010 10:57
Last Modified: 19 Sep 2010 06:01
URI: http://eprints.iisc.ac.in/id/eprint/27498

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