1bdo
From Proteopedia
(New page: 200px<br /><applet load="1bdo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bdo, resolution 1.8Å" /> '''STRUCTURE OF THE BIOT...) |
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| - | [[Image:1bdo.gif|left|200px]]<br /><applet load="1bdo" size=" | + | [[Image:1bdo.gif|left|200px]]<br /><applet load="1bdo" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1bdo, resolution 1.8Å" /> | caption="1bdo, resolution 1.8Å" /> | ||
'''STRUCTURE OF THE BIOTINYL DOMAIN OF ACETYL-COENZYME A CARBOXYLASE DETERMINED BY MAD PHASING'''<br /> | '''STRUCTURE OF THE BIOTINYL DOMAIN OF ACETYL-COENZYME A CARBOXYLASE DETERMINED BY MAD PHASING'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Acetyl-coenzyme A carboxylase catalyzes the first committed | + | BACKGROUND: Acetyl-coenzyme A carboxylase catalyzes the first committed step of fatty acid biosynthesis. Universally, this reaction involves three functional components all related to a carboxybiotinyl intermediate. A biotinyl domain shuttles its covalently attached biotin prosthetic group between the active sites of a biotin carboxylase and a carboxyl transferase. In Escherichia coli, the three components reside in separate subunits: a biotinyl domain is the functional portion of one of these, biotin carboxy carrier protein (BCCP). RESULTS: We have expressed natural and selenomethionyl (Se-met) BCCP from E. coli as biotinylated recombinant proteins, proteolyzed them with subtilisin Carlsberg to produce the biotinyl domains BCCP and Se-met BCCPsc, determined the crystal structure of Se-met BCCPsc using a modified version of the multiwavelength anomalous diffraction (MAD) phasing protocol, and refined the structure for the natural BCCPsc at 1.8 A resolution. The structure may be described as a capped beta sandwich with quasi-dyad symmetry. Each half contains a characteristic hammerhead motif. The biotinylated lysin is located at a hairpin beta turn which connects the two symmetric halves of the molecule, and its biotinyl group interacts with a non-symmetric protrusion from the core. CONCLUSIONS: This first crystal structure of a biotinyl domain helps to unravel the central role of such domains in reactions catalyzed by biotin-dependent carboxylases. The hammerhead structure observed twice in BCCPsc may be regarded as the basic structural motif of biotinyl and lipoyl domains of a superfamily of enzymes. The new MAD phasing techniques developed in the course of determining this structure enhance the power of the MAD method. |
==About this Structure== | ==About this Structure== | ||
| - | 1BDO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with BTN as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Acetyl-CoA_carboxylase Acetyl-CoA carboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.4.1.2 6.4.1.2] Full crystallographic information is available from [http:// | + | 1BDO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=BTN:'>BTN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Acetyl-CoA_carboxylase Acetyl-CoA carboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.4.1.2 6.4.1.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BDO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Athappilly, F | + | [[Category: Athappilly, F K.]] |
| - | [[Category: Hendrickson, W | + | [[Category: Hendrickson, W A.]] |
[[Category: BTN]] | [[Category: BTN]] | ||
[[Category: bccpsc]] | [[Category: bccpsc]] | ||
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[[Category: selenomethionine]] | [[Category: selenomethionine]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:54:11 2008'' |
Revision as of 09:54, 21 February 2008
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STRUCTURE OF THE BIOTINYL DOMAIN OF ACETYL-COENZYME A CARBOXYLASE DETERMINED BY MAD PHASING
Overview
BACKGROUND: Acetyl-coenzyme A carboxylase catalyzes the first committed step of fatty acid biosynthesis. Universally, this reaction involves three functional components all related to a carboxybiotinyl intermediate. A biotinyl domain shuttles its covalently attached biotin prosthetic group between the active sites of a biotin carboxylase and a carboxyl transferase. In Escherichia coli, the three components reside in separate subunits: a biotinyl domain is the functional portion of one of these, biotin carboxy carrier protein (BCCP). RESULTS: We have expressed natural and selenomethionyl (Se-met) BCCP from E. coli as biotinylated recombinant proteins, proteolyzed them with subtilisin Carlsberg to produce the biotinyl domains BCCP and Se-met BCCPsc, determined the crystal structure of Se-met BCCPsc using a modified version of the multiwavelength anomalous diffraction (MAD) phasing protocol, and refined the structure for the natural BCCPsc at 1.8 A resolution. The structure may be described as a capped beta sandwich with quasi-dyad symmetry. Each half contains a characteristic hammerhead motif. The biotinylated lysin is located at a hairpin beta turn which connects the two symmetric halves of the molecule, and its biotinyl group interacts with a non-symmetric protrusion from the core. CONCLUSIONS: This first crystal structure of a biotinyl domain helps to unravel the central role of such domains in reactions catalyzed by biotin-dependent carboxylases. The hammerhead structure observed twice in BCCPsc may be regarded as the basic structural motif of biotinyl and lipoyl domains of a superfamily of enzymes. The new MAD phasing techniques developed in the course of determining this structure enhance the power of the MAD method.
About this Structure
1BDO is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Acetyl-CoA carboxylase, with EC number 6.4.1.2 Full crystallographic information is available from OCA.
Reference
Structure of the biotinyl domain of acetyl-coenzyme A carboxylase determined by MAD phasing., Athappilly FK, Hendrickson WA, Structure. 1995 Dec 15;3(12):1407-19. PMID:8747466
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