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Title
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X-ray crystal structure of the human dimeric S-Lac lectin, L-14-II, in complex with lactose at 2.9-A resolution.
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Authors
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Y.D.Lobsanov,
M.A.Gitt,
H.Leffler,
S.H.Barondes,
J.M.Rini.
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Ref.
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J Biol Chem, 1993,
268,
27034-27038.
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PubMed id
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Abstract
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S-Lac lectins are a family of soluble lactose-binding animal lectins, some of
which have been implicated in modulating cell-cell and cell-matrix interactions
through specific carbohydrate-mediated recognition. We report here the x-ray
crystal structure of a representative member of this family, the human dimeric
S-Lac lectin, L-14-II, in complex with lactose, at 2.9-A resolution. The
two-fold symmetric dimer is made up of two extended anti-parallel beta-sheets,
which associate in a beta-sandwich motif. Remarkably, the L-14-II monomer shares
not only the same topology, but a very similar beta-sheet structure with that of
the leguminous plant lectins, suggesting a conserved structure-function
relationship. Carbohydrate binding by L-14-II was found to involve protein
residues that are very highly conserved among all S-Lac lectins. These residues
map to a single DNA exon, suggesting a carbohydrate binding cassette common to
all S-Lac lectins.
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