1cl0
From Proteopedia
(New page: 200px<br /><applet load="1cl0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cl0, resolution 2.50Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1cl0.gif|left|200px]]<br /><applet load="1cl0" size=" | + | [[Image:1cl0.gif|left|200px]]<br /><applet load="1cl0" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1cl0, resolution 2.50Å" /> | caption="1cl0, resolution 2.50Å" /> | ||
'''CRYSTAL STRUCTURE OF REDUCED THIOREDOXIN REDUCTASE FROM ESCHERICHIA COLI.'''<br /> | '''CRYSTAL STRUCTURE OF REDUCED THIOREDOXIN REDUCTASE FROM ESCHERICHIA COLI.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Catalysis by thioredoxin reductase (TrxR) from Escherichia coli requires | + | Catalysis by thioredoxin reductase (TrxR) from Escherichia coli requires alternation between two domain arrangements. One of these conformations has been observed by X-ray crystallography (Waksman G, Krishna TSR, Williams CH Jr, Kuriyan J, 1994, J Mol Biol 236:800-816). This form of TrxR, denoted FO, permits the reaction of enzyme-bound reduced FAD with a redox-active disulfide on TrxR. As part of an investigation of conformational changes and intermediates in catalysis by TrxR, an X-ray structure of the FO form of TrxR with both the FAD and active site disulfide reduced has been determined. Reduction after crystallization resulted in significant local conformation changes. The isoalloxazine ring of the FAD cofactor, which is essentially planar in the oxidized enzyme, assumes a 34 degree "butterfly" bend about the N(5)-N(10) axis in reduced TrxR. Theoretical calculations reported by others predict ring bending of 15-28 degrees for reduced isoalloxazines protonated at N(1). The large bending in reduced TrxR is attributed in part to steric interactions between the isoalloxazine ring and the sulfur of Cys138, formed by reduction of the active site disulfide, and is accompanied by changes in the positions and interactions of several of the ribityl side-chain atoms of FAD. The bending angle in reduced TrxR is larger than that for any flavoprotein in the Protein Data Bank. Distributions of bending angles in published oxidized and reduced flavoenzyme structures are different from those found in studies of free flavins, indicating that the protein environment has a significant effect on bending. |
==About this Structure== | ==About this Structure== | ||
| - | 1CL0 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 FAD as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Thioredoxin-disulfide_reductase Thioredoxin-disulfide reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.8.1.9 1.8.1.9] Full crystallographic information is available from [http:// | + | 1CL0 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=FAD:'>FAD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Thioredoxin-disulfide_reductase Thioredoxin-disulfide reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.8.1.9 1.8.1.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CL0 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thioredoxin-disulfide reductase]] | [[Category: Thioredoxin-disulfide reductase]] | ||
| - | [[Category: Jr, C | + | [[Category: Jr, C H.Williams.]] |
| - | [[Category: Lennon, B | + | [[Category: Lennon, B W.]] |
| - | [[Category: Ludwig, M | + | [[Category: Ludwig, M L.]] |
[[Category: FAD]] | [[Category: FAD]] | ||
[[Category: flavoenzyme]] | [[Category: flavoenzyme]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:07:10 2008'' |
Revision as of 10:07, 21 February 2008
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CRYSTAL STRUCTURE OF REDUCED THIOREDOXIN REDUCTASE FROM ESCHERICHIA COLI.
Overview
Catalysis by thioredoxin reductase (TrxR) from Escherichia coli requires alternation between two domain arrangements. One of these conformations has been observed by X-ray crystallography (Waksman G, Krishna TSR, Williams CH Jr, Kuriyan J, 1994, J Mol Biol 236:800-816). This form of TrxR, denoted FO, permits the reaction of enzyme-bound reduced FAD with a redox-active disulfide on TrxR. As part of an investigation of conformational changes and intermediates in catalysis by TrxR, an X-ray structure of the FO form of TrxR with both the FAD and active site disulfide reduced has been determined. Reduction after crystallization resulted in significant local conformation changes. The isoalloxazine ring of the FAD cofactor, which is essentially planar in the oxidized enzyme, assumes a 34 degree "butterfly" bend about the N(5)-N(10) axis in reduced TrxR. Theoretical calculations reported by others predict ring bending of 15-28 degrees for reduced isoalloxazines protonated at N(1). The large bending in reduced TrxR is attributed in part to steric interactions between the isoalloxazine ring and the sulfur of Cys138, formed by reduction of the active site disulfide, and is accompanied by changes in the positions and interactions of several of the ribityl side-chain atoms of FAD. The bending angle in reduced TrxR is larger than that for any flavoprotein in the Protein Data Bank. Distributions of bending angles in published oxidized and reduced flavoenzyme structures are different from those found in studies of free flavins, indicating that the protein environment has a significant effect on bending.
About this Structure
1CL0 is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Thioredoxin-disulfide reductase, with EC number 1.8.1.9 Full crystallographic information is available from OCA.
Reference
Crystal structure of reduced thioredoxin reductase from Escherichia coli: structural flexibility in the isoalloxazine ring of the flavin adenine dinucleotide cofactor., Lennon BW, Williams CH Jr, Ludwig ML, Protein Sci. 1999 Nov;8(11):2366-79. PMID:10595539
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