1sqc
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The crystal structure of squalene-hopene cyclase from Alicyclobacillus, acidocaldarius was determined at 2.9 angstrom resolution. The mechanism, and sequence of this cyclase are closely related to those of, 2,3-oxidosqualene cyclases that catalyze the cyclization step in, cholesterol biosynthesis. The structure reveals a membrane protein with, membrane-binding characteristics similar to those of prostaglandin-H2, synthase, the only other reported protein of this type. The active site of, the enzyme is located in a large central cavity that is of suitable size, to bind squalene in its required conformation and that is lined by, aromatic residues. The structure supports a mechanism in which the acid, starting the reaction by protonating a carbon-carbon double bond is an, aspartate that is . | + | The crystal structure of squalene-hopene cyclase from Alicyclobacillus, acidocaldarius was determined at 2.9 angstrom resolution. The mechanism, and sequence of this cyclase are closely related to those of, 2,3-oxidosqualene cyclases that catalyze the cyclization step in, cholesterol biosynthesis. The structure reveals a membrane protein with, membrane-binding characteristics similar to those of prostaglandin-H2, synthase, the only other reported protein of this type. The active site of, the enzyme is located in a large central cavity that is of suitable size, to bind squalene in its required conformation and that is lined by, aromatic residues. The structure supports a mechanism in which the acid, starting the reaction by protonating a carbon-carbon double bond is an, aspartate that is coupled to a histidine. Numerous surface alpha helices, are connected by characteristic QW-motifs (Q is glutamine and W is, tryptophan) that tighten the protein structure, possibly for absorbing the, reaction energy without structural damage. |
==About this Structure== | ==About this Structure== | ||
| - | 1SQC is a | + | 1SQC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Alicyclobacillus_acidocaldarius Alicyclobacillus acidocaldarius] with LDA as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: LDA. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1SQC OCA]. |
==Reference== | ==Reference== | ||
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[[Category: terpenoid metabolism]] | [[Category: terpenoid metabolism]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:24:17 2007'' |
Revision as of 11:18, 5 November 2007
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SQUALENE-HOPENE-CYCLASE FROM ALICYCLOBACILLUS ACIDOCALDARIUS
Overview
The crystal structure of squalene-hopene cyclase from Alicyclobacillus, acidocaldarius was determined at 2.9 angstrom resolution. The mechanism, and sequence of this cyclase are closely related to those of, 2,3-oxidosqualene cyclases that catalyze the cyclization step in, cholesterol biosynthesis. The structure reveals a membrane protein with, membrane-binding characteristics similar to those of prostaglandin-H2, synthase, the only other reported protein of this type. The active site of, the enzyme is located in a large central cavity that is of suitable size, to bind squalene in its required conformation and that is lined by, aromatic residues. The structure supports a mechanism in which the acid, starting the reaction by protonating a carbon-carbon double bond is an, aspartate that is coupled to a histidine. Numerous surface alpha helices, are connected by characteristic QW-motifs (Q is glutamine and W is, tryptophan) that tighten the protein structure, possibly for absorbing the, reaction energy without structural damage.
About this Structure
1SQC is a Single protein structure of sequence from Alicyclobacillus acidocaldarius with LDA as ligand. Structure known Active Site: LDA. Full crystallographic information is available from OCA.
Reference
Structure and function of a squalene cyclase., Wendt KU, Poralla K, Schulz GE, Science. 1997 Sep 19;277(5333):1811-5. PMID:9295270
Page seeded by OCA on Mon Nov 5 13:24:17 2007
