Abstract
The three-dimensional structure of the lactose complex of the Erythrina corallodendron Iectin (EcorL), a dimer of N-glycosylated subunits, was determined crystallographically and refined at 2.0 angstrom resolution to an R value of 0.19. The tertiary structure of the subunit is similar to that of other legume lectins, but interference by the bulky N-linked heptasaccharide, which is exceptionally well ordered in the crystal, forces die EcorL dimer into a drastically different quaternary structure. Only the galactose moiety of the lactose ligand resides within the combining site. The galactose moiety is oriented differently from ligands in the mannose-glucose specific legume lectins and is held by hydrophobic interactions with Ala88, Tyr106, Phe131, and Ala218 and by seven hydrogen bonds, four of which are to the conserved Asp89, Asn133, and NH of Gly107. The specificity of legume lectins toward the different C-4 epimers appears to be associated with extensive variations in the outline of the variable parts of the binding sites.
Original language | English |
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Pages (from-to) | 862-866 |
Number of pages | 5 |
Journal | Science |
Volume | 254 |
Issue number | 5033 |
State | Published - 8 Nov 1991 |
Externally published | Yes |
ASJC Scopus subject areas
- General