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| | {{STRUCTURE_1fiy| PDB=1fiy | SCENE= }} | | {{STRUCTURE_1fiy| PDB=1fiy | SCENE= }} |
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| - | '''THREE-DIMENSIONAL STRUCTURE OF PHOSPHOENOLPYRUVATE CARBOXYLASE FROM ESCHERICHIA COLI AT 2.8 A RESOLUTION'''
| + | ===THREE-DIMENSIONAL STRUCTURE OF PHOSPHOENOLPYRUVATE CARBOXYLASE FROM ESCHERICHIA COLI AT 2.8 A RESOLUTION=== |
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| - | ==Overview==
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| - | The crystal structure of phosphoenolpyruvate carboxylase (PEPC; EC 4. 1.1.31) has been determined by x-ray diffraction methods at 2.8-A resolution by using Escherichia coli PEPC complexed with L-aspartate, an allosteric inhibitor of all known PEPCs. The four subunits are arranged in a "dimer-of-dimers" form with respect to subunit contact, resulting in an overall square arrangement. The contents of alpha-helices and beta-strands are 65% and 5%, respectively. All of the eight beta-strands, which are widely dispersed in the primary structure, participate in the formation of a single beta-barrel. Replacement of a conserved Arg residue (Arg-438) in this linkage with Cys increased the tendency of the enzyme to dissociate into dimers. The location of the catalytic site is likely to be near the C-terminal side of the beta-barrel. The binding site for L-aspartate is located about 20 A away from the catalytic site, and four residues (Lys-773, Arg-832, Arg-587, and Asn-881) are involved in effector binding. The participation of Arg-587 is unexpected, because it is known to be catalytically essential. Because this residue is in a highly conserved glycine-rich loop, which is characteristic of PEPC, L-aspartate seemingly causes inhibition by removing this glycine-rich loop from the catalytic site. There is another mobile loop from Lys-702 to Gly-708 that is missing in the crystal structure. The importance of this loop in catalytic activity was also shown. Thus, the crystal-structure determination of PEPC revealed two mobile loops bearing the enzymatic functions and accompanying allosteric inhibition by L-aspartate.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9927652}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 9927652 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_9927652}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Carboxylase]] | | [[Category: Carboxylase]] |
| | [[Category: Phosphoenolpyruvate]] | | [[Category: Phosphoenolpyruvate]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 16:22:55 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 03:20:32 2008'' |
Revision as of 00:20, 1 July 2008
Template:STRUCTURE 1fiy
THREE-DIMENSIONAL STRUCTURE OF PHOSPHOENOLPYRUVATE CARBOXYLASE FROM ESCHERICHIA COLI AT 2.8 A RESOLUTION
Template:ABSTRACT PUBMED 9927652
About this Structure
1FIY is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of phosphoenolpyruvate carboxylase: a proposed mechanism for allosteric inhibition., Kai Y, Matsumura H, Inoue T, Terada K, Nagara Y, Yoshinaga T, Kihara A, Tsumura K, Izui K, Proc Natl Acad Sci U S A. 1999 Feb 2;96(3):823-8. PMID:9927652
Page seeded by OCA on Tue Jul 1 03:20:32 2008
