1zi7
From Proteopedia
(New page: 200px<br /><applet load="1zi7" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zi7, resolution 2.50Å" /> '''Structure of truncat...) |
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| - | [[Image:1zi7.gif|left|200px]]<br /><applet load="1zi7" size=" | + | [[Image:1zi7.gif|left|200px]]<br /><applet load="1zi7" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1zi7, resolution 2.50Å" /> | caption="1zi7, resolution 2.50Å" /> | ||
'''Structure of truncated yeast oxysterol binding protein Osh4'''<br /> | '''Structure of truncated yeast oxysterol binding protein Osh4'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The oxysterol-binding-protein (OSBP)-related proteins (ORPs) are conserved | + | The oxysterol-binding-protein (OSBP)-related proteins (ORPs) are conserved from yeast to humans, and are implicated in the regulation of sterol homeostasis and in signal transduction pathways. Here we report the structure of the full-length yeast ORP Osh4 (also known as Kes1) at 1.5-1.9 A resolution in complexes with ergosterol, cholesterol, and 7-, 20- and 25-hydroxycholesterol. We find that a single sterol molecule binds within a hydrophobic tunnel in a manner consistent with a transport function for ORPs. The entrance is blocked by a flexible amino-terminal lid and surrounded by basic residues that are critical for Osh4 function. The structure of the open state of a lid-truncated form of Osh4 was determined at 2.5 A resolution. Structural analysis and limited proteolysis show that sterol binding closes the lid and stabilizes a conformation favouring transport across aqueous barriers and signal transmission. The structure of Osh4 in the absence of ligand exposes potential phospholipid-binding sites that are positioned for membrane docking and sterol exchange. On the basis of these observations, we propose a model in which sterol and membrane binding promote reciprocal conformational changes that facilitate a sterol transfer and signalling cycle. |
==About this Structure== | ==About this Structure== | ||
| - | 1ZI7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1ZI7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZI7 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Hurley, J | + | [[Category: Hurley, J H.]] |
| - | [[Category: Im, Y | + | [[Category: Im, Y J.]] |
| - | [[Category: Prinz, W | + | [[Category: Prinz, W A.]] |
[[Category: Raychaudhuri, S.]] | [[Category: Raychaudhuri, S.]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
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[[Category: sterol binding protein]] | [[Category: sterol binding protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:15:47 2008'' |
Revision as of 14:15, 21 February 2008
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Structure of truncated yeast oxysterol binding protein Osh4
Overview
The oxysterol-binding-protein (OSBP)-related proteins (ORPs) are conserved from yeast to humans, and are implicated in the regulation of sterol homeostasis and in signal transduction pathways. Here we report the structure of the full-length yeast ORP Osh4 (also known as Kes1) at 1.5-1.9 A resolution in complexes with ergosterol, cholesterol, and 7-, 20- and 25-hydroxycholesterol. We find that a single sterol molecule binds within a hydrophobic tunnel in a manner consistent with a transport function for ORPs. The entrance is blocked by a flexible amino-terminal lid and surrounded by basic residues that are critical for Osh4 function. The structure of the open state of a lid-truncated form of Osh4 was determined at 2.5 A resolution. Structural analysis and limited proteolysis show that sterol binding closes the lid and stabilizes a conformation favouring transport across aqueous barriers and signal transmission. The structure of Osh4 in the absence of ligand exposes potential phospholipid-binding sites that are positioned for membrane docking and sterol exchange. On the basis of these observations, we propose a model in which sterol and membrane binding promote reciprocal conformational changes that facilitate a sterol transfer and signalling cycle.
About this Structure
1ZI7 is a Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Full crystallographic information is available from OCA.
Reference
Structural mechanism for sterol sensing and transport by OSBP-related proteins., Im YJ, Raychaudhuri S, Prinz WA, Hurley JH, Nature. 2005 Sep 1;437(7055):154-8. PMID:16136145
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