2ggu
From Proteopedia
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crystal structure of the trimeric neck and carbohydrate recognition domain of human surfactant protein D in complex with maltotriose
Overview
Surfactant protein D (SP-D) is an innate immune effector that contributes, to antimicrobial host defense and immune regulation. Interactions of SP-D, with microorganisms and organic antigens involve binding of, glycoconjugates to the C-type lectin carbohydrate recognition domain, (CRD). A trimeric fusion protein encoding the human neck+CRD bound to the, aromatic glycoside p-nitrophenyl-alpha-D-maltoside with nearly a log-fold, higher affinity than maltose, the prototypical competitor. Maltotriose, which has the same linkage pattern as the maltoside, bound with, intermediate affinity. Site-directed substitution of leucine for, phenylalanine 335 (Phe-335) decreased affinities for the maltoside and, maltotriose without significantly altering the affinity for maltose or, glucose, and substitution of tyrosine or tryptophan for leucine restored, preferential binding to maltotriose and the maltoside. A mutant with, alanine at this position failed to bind to mannan or maltose-substituted, solid supports. Crystallographic analysis of the human neck+CRD complexed, with maltotriose or p-nitrophenyl-maltoside showed stacking of the, terminal glucose or nitrophenyl ring with the aromatic ring of Phe-335., Our studies indicate that Phe-335, which is evolutionarily conserved in, all known SP-Ds, plays important, if not critical, roles in SP-D function.
About this Structure
2GGU is a Single protein structure of sequence from Homo sapiens with CA and MLR as ligands. Full crystallographic information is available from OCA.
Reference
Contributions of phenylalanine 335 to ligand recognition by human surfactant protein D: ring interactions with SP-D ligands., Crouch E, McDonald B, Smith K, Cafarella T, Seaton B, Head J, J Biol Chem. 2006 Jun 30;281(26):18008-14. Epub 2006 Apr 24. PMID:16636058
Page seeded by OCA on Mon Nov 12 22:18:37 2007
