1trb
From Proteopedia
(New page: 200px<br /><applet load="1trb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1trb, resolution 2.0Å" /> '''CONVERGENT EVOLUTION ...) |
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| - | [[Image:1trb.gif|left|200px]]<br /><applet load="1trb" size=" | + | [[Image:1trb.gif|left|200px]]<br /><applet load="1trb" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1trb, resolution 2.0Å" /> | caption="1trb, resolution 2.0Å" /> | ||
'''CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES'''<br /> | '''CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES'''<br /> | ||
==Overview== | ==Overview== | ||
| - | An example of two related enzymes that catalyse similar reactions but | + | An example of two related enzymes that catalyse similar reactions but possess different active sites is provided by comparing the structure of Escherichia coli thioredoxin reductase with glutathione reductase. Both are dimeric enzymes that catalyse the reduction of disulphides by pyridine nucleotides through an enzyme disulphide and a flavin. Human glutathione reductase contains four structural domains within each molecule: the flavin-adenine dinucleotide (FAD)- and nicotinamide-adenine dinucleotide phosphate (NADPH)-binding domains, the 'central' domain and the C-terminal domain that provides the dimer interface and part of the active site. Although both enzymes share the same catalytic mechanism and similar tertiary structures, their active sites do not resemble each other. We have determined the crystal structure of E. coli thioredoxin reductase at 2 A resolution, and show that thioredoxin reductase lacks the domain that provides the dimer interface in glutathione reductase, and forms a completely different dimeric structure. The catalytically active disulphides are located in different domains on opposite sides of the flavin ring system. This suggests that these enzymes diverged from an ancestral nucleotide-binding protein and acquired their disulphide reductase activities independently. |
==About this Structure== | ==About this Structure== | ||
| - | 1TRB 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:// | + | 1TRB 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=1TRB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thioredoxin-disulfide reductase]] | [[Category: Thioredoxin-disulfide reductase]] | ||
| - | [[Category: Krishna, T | + | [[Category: Krishna, T S.R.]] |
[[Category: Kuriyan, J.]] | [[Category: Kuriyan, J.]] | ||
[[Category: FAD]] | [[Category: FAD]] | ||
[[Category: oxidoreductase(flavoenzyme)]] | [[Category: oxidoreductase(flavoenzyme)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:16:32 2008'' |
Revision as of 13:16, 21 February 2008
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CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES
Overview
An example of two related enzymes that catalyse similar reactions but possess different active sites is provided by comparing the structure of Escherichia coli thioredoxin reductase with glutathione reductase. Both are dimeric enzymes that catalyse the reduction of disulphides by pyridine nucleotides through an enzyme disulphide and a flavin. Human glutathione reductase contains four structural domains within each molecule: the flavin-adenine dinucleotide (FAD)- and nicotinamide-adenine dinucleotide phosphate (NADPH)-binding domains, the 'central' domain and the C-terminal domain that provides the dimer interface and part of the active site. Although both enzymes share the same catalytic mechanism and similar tertiary structures, their active sites do not resemble each other. We have determined the crystal structure of E. coli thioredoxin reductase at 2 A resolution, and show that thioredoxin reductase lacks the domain that provides the dimer interface in glutathione reductase, and forms a completely different dimeric structure. The catalytically active disulphides are located in different domains on opposite sides of the flavin ring system. This suggests that these enzymes diverged from an ancestral nucleotide-binding protein and acquired their disulphide reductase activities independently.
About this Structure
1TRB 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
Convergent evolution of similar function in two structurally divergent enzymes., Kuriyan J, Krishna TS, Wong L, Guenther B, Pahler A, Williams CH Jr, Model P, Nature. 1991 Jul 11;352(6331):172-4. PMID:2067578
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