1oql

Mistletoe Lectin I from Viscum album complexed with galactose

spinqualitylabelsall models 1oql, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1oql is a 2 chain structure with sequence from Viscum album. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3Å Ligands: GAL, NAG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ML1_VISAL The A chain is responsible for inhibiting protein synthesis through the catalytic inactivation of 60S ribosomal subunits by removing adenine from position 4,324 of 28S rRNA. The B chain binds to cell receptors and probably facilitates the entry into the cell of the A chain; B chains are also responsible for cell agglutination (lectin activity). Inhibits growth of the human tumor cell line Molt4. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The X-ray structure of mistletoe lectin I (MLI), a type-II ribosome-inactivating protein (RIP), cocrystallized with galactose is described. The model was refined at 3.0 A resolution to an R-factor of 19.9% using 21 899 reflections, with Rfree 24.0%. MLI forms a homodimer (A-B)2 in the crystal, as it does in solution at high concentration. The dimer is formed through contacts between the N-terminal domains of two B-chains involving weak polar and non-polar interactions. Consequently, the overall arrangement of sugar-binding sites in MLI differs from those in monomeric type-II RIPs: two N-terminal sugar-binding sites are 15 A apart on one side of the dimer, and two C-terminal sugar-binding sites are 87 A apart on the other side. Galactose binding is achieved by common hydrogen bonds for the two binding sites via hydroxy groups 3-OH and 4-OH and hydrophobic contact by an aromatic ring. In addition, at the N-terminal site 2-OH forms hydrogen bonds with Asp27 and Lys41, and at the C-terminal site 3-OH and 6-OH undergo water-mediated interactions and C5 has a hydrophobic contact. MLI is a galactose-specific lectin and shows little affinity for N-acetylgalactosamine. The reason for this is discussed. Structural differences among the RIPs investigated in this study (their quaternary structures, location of sugar-binding sites, and fine sugar specificities of their B-chains, which could have diverged through evolution from a two-domain protein) may affect the binding sites, and consequently the cellular transport processes and biological responses of these toxins. Crystal structure at 3 A of mistletoe lectin I, a dimeric type-II ribosome-inactivating protein, complexed with galactose.,Niwa H, Tonevitsky AG, Agapov II, Saward S, Pfuller U, Palmer RA Eur J Biochem. 2003 Jul;270(13):2739-49. PMID:12823544 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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