1oql
From Proteopedia
(New page: 200px<br /><applet load="1oql" size="450" color="white" frame="true" align="right" spinBox="true" caption="1oql, resolution 3.0Å" /> '''Mistletoe Lectin I fr...) |
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| - | [[Image:1oql.gif|left|200px]]<br /><applet load="1oql" size=" | + | [[Image:1oql.gif|left|200px]]<br /><applet load="1oql" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1oql, resolution 3.0Å" /> | caption="1oql, resolution 3.0Å" /> | ||
'''Mistletoe Lectin I from Viscum album complexed with galactose'''<br /> | '''Mistletoe Lectin I from Viscum album complexed with galactose'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray structure of mistletoe lectin I (MLI), a type-II | + | 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== | ==About this Structure== | ||
| - | 1OQL is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Viscum_album Viscum album] with GAL and NAG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/rRNA_N-glycosylase rRNA N-glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.22 3.2.2.22] Full crystallographic information is available from [http:// | + | 1OQL is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Viscum_album Viscum album] with <scene name='pdbligand=GAL:'>GAL</scene> and <scene name='pdbligand=NAG:'>NAG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/rRNA_N-glycosylase rRNA N-glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.22 3.2.2.22] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OQL OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Viscum album]] | [[Category: Viscum album]] | ||
[[Category: rRNA N-glycosylase]] | [[Category: rRNA N-glycosylase]] | ||
| - | [[Category: Agapov, I | + | [[Category: Agapov, I I.]] |
[[Category: Niwa, H.]] | [[Category: Niwa, H.]] | ||
| - | [[Category: Palmer, R | + | [[Category: Palmer, R A.]] |
[[Category: Pfuller, U.]] | [[Category: Pfuller, U.]] | ||
[[Category: Saward, S.]] | [[Category: Saward, S.]] | ||
| - | [[Category: Tonevitsky, A | + | [[Category: Tonevitsky, A G.]] |
[[Category: GAL]] | [[Category: GAL]] | ||
[[Category: NAG]] | [[Category: NAG]] | ||
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[[Category: type-ii ribosome-inactivating protein]] | [[Category: type-ii ribosome-inactivating protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:20:31 2008'' |
Revision as of 12:20, 21 February 2008
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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 with and as ligands. Active as rRNA N-glycosylase, with EC number 3.2.2.22 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
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