4cts
From Proteopedia
(New page: 200px<br /><applet load="4cts" size="450" color="white" frame="true" align="right" spinBox="true" caption="4cts, resolution 2.9Å" /> '''CRYSTAL STRUCTURE ANA...) |
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| - | [[Image:4cts.gif|left|200px]]<br /><applet load="4cts" size=" | + | [[Image:4cts.gif|left|200px]]<br /><applet load="4cts" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="4cts, resolution 2.9Å" /> | caption="4cts, resolution 2.9Å" /> | ||
'''CRYSTAL STRUCTURE ANALYSIS AND MOLECULAR MODEL OF A COMPLEX OF CITRATE SYNTHASE WITH OXALOACETATE AND S-ACETONYL-COENZYME A'''<br /> | '''CRYSTAL STRUCTURE ANALYSIS AND MOLECULAR MODEL OF A COMPLEX OF CITRATE SYNTHASE WITH OXALOACETATE AND S-ACETONYL-COENZYME A'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structure of the complex of pig heart citrate synthase and | + | The crystal structure of the complex of pig heart citrate synthase and oxaloacetate in the presence of the potent inhibitor S-acetonyl coenzyme A has been determined at a nominal resolution of 2.9 A by Patterson search techniques and refined by restrained crystallographic refinement. The complex crystallizes in the presence of polyvinylpyrrolidone in space group P4(3)2(1)2 with a = 101.5 A and c = 224.6 A, with one dimeric molecule of molecular weight 100,000 in the asymmetric unit. The crystallographic R factor is 0.194 for the 14,332 unique reflections between 6.0 and 2.9 A resolution. The structures of two forms of citrate synthase in the presence and absence of product molecules have been determined recently and shown to differ in the relative arrangement of the large and small domains ("closed" and "open" forms). The third crystal form described here is also closed, but there is substantial rearrangement within the small domain relative to either of the other crystal forms. We conclude that this is a third structural state of the enzyme, and catalytic activity of the enzyme depends on structural changes during the course of the reaction affecting domain conformation also. The three structures are compared, and it is shown that the large domain is considerably more rigid than the small domain. The conformation of the small domain adapts to the ligand. The inhibitor, and the "coenzyme-A-binding segment" of the enzyme are disordered. No electron density is observed for the inhibitor, and only weak density for the coenzyme-A-binding segment. Electron density for oxaloacetate is well defined. It binds in a very similar manner to citrate. |
==About this Structure== | ==About this Structure== | ||
| - | 4CTS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with OAA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Citrate_(Si)-synthase Citrate (Si)-synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.3.1 2.3.3.1] Full crystallographic information is available from [http:// | + | 4CTS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=OAA:'>OAA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Citrate_(Si)-synthase Citrate (Si)-synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.3.1 2.3.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4CTS OCA]. |
==Reference== | ==Reference== | ||
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[[Category: oxo-acid-lyase]] | [[Category: oxo-acid-lyase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:13:05 2008'' |
Revision as of 17:13, 21 February 2008
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CRYSTAL STRUCTURE ANALYSIS AND MOLECULAR MODEL OF A COMPLEX OF CITRATE SYNTHASE WITH OXALOACETATE AND S-ACETONYL-COENZYME A
Overview
The crystal structure of the complex of pig heart citrate synthase and oxaloacetate in the presence of the potent inhibitor S-acetonyl coenzyme A has been determined at a nominal resolution of 2.9 A by Patterson search techniques and refined by restrained crystallographic refinement. The complex crystallizes in the presence of polyvinylpyrrolidone in space group P4(3)2(1)2 with a = 101.5 A and c = 224.6 A, with one dimeric molecule of molecular weight 100,000 in the asymmetric unit. The crystallographic R factor is 0.194 for the 14,332 unique reflections between 6.0 and 2.9 A resolution. The structures of two forms of citrate synthase in the presence and absence of product molecules have been determined recently and shown to differ in the relative arrangement of the large and small domains ("closed" and "open" forms). The third crystal form described here is also closed, but there is substantial rearrangement within the small domain relative to either of the other crystal forms. We conclude that this is a third structural state of the enzyme, and catalytic activity of the enzyme depends on structural changes during the course of the reaction affecting domain conformation also. The three structures are compared, and it is shown that the large domain is considerably more rigid than the small domain. The conformation of the small domain adapts to the ligand. The inhibitor, and the "coenzyme-A-binding segment" of the enzyme are disordered. No electron density is observed for the inhibitor, and only weak density for the coenzyme-A-binding segment. Electron density for oxaloacetate is well defined. It binds in a very similar manner to citrate.
About this Structure
4CTS is a Single protein structure of sequence from Sus scrofa with as ligand. Active as Citrate (Si)-synthase, with EC number 2.3.3.1 Full crystallographic information is available from OCA.
Reference
Crystal structure analysis and molecular model of a complex of citrate synthase with oxaloacetate and S-acetonyl-coenzyme A., Wiegand G, Remington S, Deisenhofer J, Huber R, J Mol Biol. 1984 Mar 25;174(1):205-19. PMID:6716477
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