4m18

Crystal Structure of Surfactant Protein-D D325A/R343V mutant in complex with trimannose (Man-a1,2Man-a1,2Man)Crystal Structure of Surfactant Protein-D D325A/R343V mutant in complex with trimannose (Man-a1,2Man-a1,2Man)

Structural highlights 4m18 is a 12 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.203Å Ligands: , , Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SFTPD_HUMAN Contributes to the lung's defense against inhaled microorganisms. May participate in the extracellular reorganization or turnover of pulmonary surfactant. Binds strongly maltose residues and to a lesser extent other alpha-glucosyl moieties. Publication Abstract from PubMed Surfactant protein D (SP-D), a mammalian C-type lectin, is the primary innate inhibitor of influenza A virus (IAV) in the lung. Interactions of SP-D with highly branched viral N-linked glycans on hemagglutinin (HA), an abundant IAV envelope protein and critical virulence factor, promote viral aggregation and neutralization through as yet unknown molecular mechanisms. Two truncated human SP-D forms, wild-type (WT) and double mutant D325A+R343V, representing neck and carbohydrate recognition domains are compared in this study. Whereas both WT and D325A+R343V bind to isolated glycosylated HA, WT does not inhibit IAV in neutralization assays; in contrast, D325A+R343V neutralization compares well with that of full-length native SP-D. To elucidate the mechanism for these biochemical observations, we have determined crystal structures of D325A+R343V in the presence and absence of a viral nonamannoside (Man9). On the basis of the D325A+R343V-Man9 structure and other crystallographic data, models of complexes between HA and WT or D325A+R343V were produced and subjected to molecular dynamics. Simulations reveal that whereas WT and D325A+R343V both block the sialic acid receptor site of HA, the D325A+R343V complex is more stable, with stronger binding caused by additional hydrogen bonds and hydrophobic interactions with HA residues. Furthermore, the blocking mechanism of HA differs for WT and D325A+R343V because of alternate glycan binding modes. The combined results suggest a mechanism through which the mode of SP-D-HA interaction could significantly influence viral aggregation and neutralization. These studies provide the first atomic-level molecular view of an innate host defense lectin inhibiting its viral glycoprotein target. Molecular mechanisms of inhibition of influenza by surfactant protein d revealed by large-scale molecular dynamics simulation.,Goh BC, Rynkiewicz MJ, Cafarella TR, White MR, Hartshorn KL, Allen K, Crouch EC, Calin O, Seeberger PH, Schulten K, Seaton BA Biochemistry. 2013 Nov 26;52(47):8527-38. doi: 10.1021/bi4010683. Epub 2013 Nov, 13. PMID:24224757 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

spinqualitylabelsall models 4m18, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image