1cnq
From Proteopedia
(New page: 200px<br /><applet load="1cnq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cnq, resolution 2.27Å" /> '''FRUCTOSE-1,6-BISPHOS...) |
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| - | [[Image:1cnq.jpg|left|200px]]<br /><applet load="1cnq" size=" | + | [[Image:1cnq.jpg|left|200px]]<br /><applet load="1cnq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1cnq, resolution 2.27Å" /> | caption="1cnq, resolution 2.27Å" /> | ||
'''FRUCTOSE-1,6-BISPHOSPHATASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE AND ZINC IONS'''<br /> | '''FRUCTOSE-1,6-BISPHOSPHATASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE AND ZINC IONS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | A disordered loop (loop 52-72, residues 52-72) in crystal structures of | + | A disordered loop (loop 52-72, residues 52-72) in crystal structures of fructose-1,6-bisphosphatase (FBPase) has been implicated in regulatory and catalytic phenomena by studies in directed mutation. A crystal structure of FBPase in a complex with three zinc cations and the products fructose 6-phosphate (F6P) and phosphate (Pi) reveals loop 52-72 for the first time in a well-defined conformation with strong electron density. Loop 52-57 interacts primarily with the active site of its own subunit. Asp68 of the loop hydrogen bonds with Arg276 and a zinc cation located at the putative potassium activation site. Leu56 and Tyr57 of the loop pack against hydrophobic residues from two separate subunits of FBPase. A mechanism of allosteric regulation of catalysis is presented, in which AMP, by binding to its allosteric pocket, displaces loop 52-72 from the active site. Furthermore, the current structure suggests that both the alpha- and beta-anomers of F6P can be substrates in the reverse reaction catalyzed by FBPase. Mechanisms of catalysis are proposed for the reverse reaction in which Asp121 serves as a catalytic base for the alpha-anomer and Glu280 serves as a catalytic base for the beta-anomer. |
==About this Structure== | ==About this Structure== | ||
| - | 1CNQ 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 F6P, ZN and PO4 as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 1CNQ 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=F6P:'>F6P</scene>, <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1BFL. Active as [http://en.wikipedia.org/wiki/Fructose-bisphosphatase Fructose-bisphosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.11 3.1.3.11] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CNQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Fromm, H.]] | [[Category: Fromm, H.]] | ||
[[Category: Honzatko, R.]] | [[Category: Honzatko, R.]] | ||
| - | [[Category: Poland, B | + | [[Category: Poland, B W.]] |
[[Category: F6P]] | [[Category: F6P]] | ||
[[Category: PO4]] | [[Category: PO4]] | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:07:55 2008'' |
Revision as of 10:07, 21 February 2008
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FRUCTOSE-1,6-BISPHOSPHATASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE AND ZINC IONS
Overview
A disordered loop (loop 52-72, residues 52-72) in crystal structures of fructose-1,6-bisphosphatase (FBPase) has been implicated in regulatory and catalytic phenomena by studies in directed mutation. A crystal structure of FBPase in a complex with three zinc cations and the products fructose 6-phosphate (F6P) and phosphate (Pi) reveals loop 52-72 for the first time in a well-defined conformation with strong electron density. Loop 52-57 interacts primarily with the active site of its own subunit. Asp68 of the loop hydrogen bonds with Arg276 and a zinc cation located at the putative potassium activation site. Leu56 and Tyr57 of the loop pack against hydrophobic residues from two separate subunits of FBPase. A mechanism of allosteric regulation of catalysis is presented, in which AMP, by binding to its allosteric pocket, displaces loop 52-72 from the active site. Furthermore, the current structure suggests that both the alpha- and beta-anomers of F6P can be substrates in the reverse reaction catalyzed by FBPase. Mechanisms of catalysis are proposed for the reverse reaction in which Asp121 serves as a catalytic base for the alpha-anomer and Glu280 serves as a catalytic base for the beta-anomer.
About this Structure
1CNQ is a Single protein structure of sequence from Sus scrofa with , and as ligands. This structure supersedes the now removed PDB entry 1BFL. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 Full crystallographic information is available from OCA.
Reference
Role of a dynamic loop in cation activation and allosteric regulation of recombinant porcine fructose-1,6-bisphosphatase., Choe JY, Poland BW, Fromm HJ, Honzatko RB, Biochemistry. 1998 Aug 18;37(33):11441-50. PMID:9708979
Page seeded by OCA on Thu Feb 21 12:07:55 2008
Categories: Fructose-bisphosphatase | Single protein | Sus scrofa | Choe, J. | Fromm, H. | Honzatko, R. | Poland, B W. | F6P | PO4 | ZN | Bisphosphatase | Hydrolase
