1am9
From Proteopedia
(New page: 200px<br /> <applet load="1am9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1am9, resolution 2.300Å" /> '''HUMAN SREBP-1A BOU...) |
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| - | [[Image:1am9.gif|left|200px]]<br /> | + | [[Image:1am9.gif|left|200px]]<br /><applet load="1am9" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1am9" size=" | + | |
caption="1am9, resolution 2.300Å" /> | caption="1am9, resolution 2.300Å" /> | ||
'''HUMAN SREBP-1A BOUND TO LDL RECEPTOR PROMOTER'''<br /> | '''HUMAN SREBP-1A BOUND TO LDL RECEPTOR PROMOTER'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: The sterol regulatory element binding proteins (SREBPs) are | + | BACKGROUND: The sterol regulatory element binding proteins (SREBPs) are helix-loop-helix transcriptional activators that control expression of genes encoding proteins essential for cholesterol biosynthesis/uptake and fatty acid biosynthesis. Unlike helix-loop-helix proteins that recognize symmetric E-boxes (5'-CANNTG-3'), the SREBPs have a tyrosine instead of a conserved arginine in their basic regions. This difference allows recognition of an asymmetric sterol regulatory element (StRE, 5'-ATCACCCAC-3'). RESULTS: The 2.3 A resolution co-crystal structure of the DNA-binding portion of SREBP-1a bound to an StRE reveals a quasi-symmetric homodimer with an asymmetric DNA-protein interface. One monomer binds the E-box half site of the StRE (5'-ATCAC-3') using sidechain-base contacts typical of other helix-loop-helix proteins. The non-E-box half site (5'-GTGGG-3') is recognized through entirely different protein-DNA contacts. CONCLUSIONS: Although the SREBPs are structurally similar to the E-box-binding helix-loop-helix proteins, the Arg-->Tyr substitution yields dramatically different DNA-binding properties that explain how they recognize StREs and regulate expression of genes important for membrane biosynthesis. |
==About this Structure== | ==About this Structure== | ||
| - | 1AM9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1AM9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AM9 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Burley, S | + | [[Category: Burley, S K.]] |
[[Category: Parraga, A.]] | [[Category: Parraga, A.]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: transcription factor]] | [[Category: transcription factor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:45:59 2008'' |
Revision as of 09:46, 21 February 2008
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HUMAN SREBP-1A BOUND TO LDL RECEPTOR PROMOTER
Overview
BACKGROUND: The sterol regulatory element binding proteins (SREBPs) are helix-loop-helix transcriptional activators that control expression of genes encoding proteins essential for cholesterol biosynthesis/uptake and fatty acid biosynthesis. Unlike helix-loop-helix proteins that recognize symmetric E-boxes (5'-CANNTG-3'), the SREBPs have a tyrosine instead of a conserved arginine in their basic regions. This difference allows recognition of an asymmetric sterol regulatory element (StRE, 5'-ATCACCCAC-3'). RESULTS: The 2.3 A resolution co-crystal structure of the DNA-binding portion of SREBP-1a bound to an StRE reveals a quasi-symmetric homodimer with an asymmetric DNA-protein interface. One monomer binds the E-box half site of the StRE (5'-ATCAC-3') using sidechain-base contacts typical of other helix-loop-helix proteins. The non-E-box half site (5'-GTGGG-3') is recognized through entirely different protein-DNA contacts. CONCLUSIONS: Although the SREBPs are structurally similar to the E-box-binding helix-loop-helix proteins, the Arg-->Tyr substitution yields dramatically different DNA-binding properties that explain how they recognize StREs and regulate expression of genes important for membrane biosynthesis.
About this Structure
1AM9 is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
Reference
Co-crystal structure of sterol regulatory element binding protein 1a at 2.3 A resolution., Parraga A, Bellsolell L, Ferre-D'Amare AR, Burley SK, Structure. 1998 May 15;6(5):661-72. PMID:9634703
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