1oql
From Proteopedia
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'''Mistletoe Lectin I from Viscum album complexed with galactose''' | '''Mistletoe Lectin I from Viscum album complexed with galactose''' | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Viscum album]] | [[Category: Viscum album]] | ||
| - | [[Category: | + | [[Category: RRNA N-glycosylase]] |
[[Category: Agapov, I I.]] | [[Category: Agapov, I I.]] | ||
[[Category: Niwa, H.]] | [[Category: Niwa, H.]] | ||
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[[Category: Saward, S.]] | [[Category: Saward, S.]] | ||
[[Category: Tonevitsky, A G.]] | [[Category: Tonevitsky, A G.]] | ||
| - | [[Category: | + | [[Category: Beta-trefoil]] |
| - | [[Category: | + | [[Category: Ricin-like]] |
| - | [[Category: | + | [[Category: Type-ii ribosome-inactivating protein]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 04:09:56 2008'' | |
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Revision as of 01:09, 3 May 2008
Mistletoe Lectin I from Viscum album complexed with galactose
Overview
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.
About this Structure
1OQL is a Protein complex structure of sequences from Viscum album. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Sat May 3 04:09:56 2008
