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1am9

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HUMAN SREBP-1A BOUND TO LDL RECEPTOR PROMOTER

Structural highlights

1am9 is a 8 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.3Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SRBP1_HUMAN Transcriptional activator required for lipid homeostasis. Regulates transcription of the LDL receptor gene as well as the fatty acid and to a lesser degree the cholesterol synthesis pathway (By similarity). Binds to the sterol regulatory element 1 (SRE-1) (5'-ATCACCCCAC-3'). Has dual sequence specificity binding to both an E-box motif (5'-ATCACGTGA-3') and to SRE-1 (5'-ATCACCCCAC-3').

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

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.

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^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Parraga A, Bellsolell L, Ferre-D'Amare AR, Burley SK. Co-crystal structure of sterol regulatory element binding protein 1a at 2.3 A resolution. Structure. 1998 May 15;6(5):661-72. PMID:9634703