The structure of phytohemagglutinin-L (PHA-L), a leucoagglutinating seed lectin from Phaseolus vulgaris, has been solved with molecular replacement using the coordinates of lentil lectin as model, and refined at a resolution of 2.8 A. The final R-factor of the structure is 20 ...
The structure of phytohemagglutinin-L (PHA-L), a leucoagglutinating seed lectin from Phaseolus vulgaris, has been solved with molecular replacement using the coordinates of lentil lectin as model, and refined at a resolution of 2.8 A. The final R-factor of the structure is 20.0%. The quaternary structure of the PHA-L tetramer differs from the structures of the concanavalin A and peanut lectin tetramers, but resembles the structure of the soybean agglutinin tetramer. PHA-L consists of two canonical legume lectin dimers that pack together through the formation of a close contact between two beta-strands. Of the two covalently bound oligosaccharides per monomer, only one GlcNAc residue per monomer is visible in the electron density. In this article we describe the structure of PHA-L, and we discuss the putative position of the high affinity adenine-binding site present in a number of legume lectins. A comparison with transthyretin, a protein that shows a remarkable resemblance to PHA-L, gives further ground to our proposal.
Related Citations:
Crystallization of Glycosylated and Nonglycosylated Phytohemagglutinin-L Dao-Thi, M.H., Hamelryck, T.W., Poortmans, F., Voelker, T.A., Chrispeels, M.J., Wyns, L. (1996) Proteins 24: 134
Lectins, Lectin Genes, and Their Role in Plant Defense Chrispeels, M.J., Raikhel, N.V. (1991) Plant Cell 3: 1
Characterization of Two Phaseolus Vulgaris Phytohemagglutinin Genes Closely Linked on the Chromosome Hoffman, L.M., Donaldson, D.D. (1985) EMBO J 4: 883
Organizational Affiliation:
Dienst Ultrastructuur, Vlaams Interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Paardenstraat 65, B-1640 Sint-Genesius-Rode, Belgium.
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