1trb: Difference between revisions

Revision as of 10:17, 3 May 2008

CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES

OverviewOverview

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 StructureAbout this Structure

1TRB is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Sat May 3 10:17:01 2008

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OCA

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 [[Image:1trb.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1trb |SIZE=350|CAPTION= <scene name='initialview01'>1trb</scene>, resolution 2.0&Aring;
+The line below this paragraph, containing "STRUCTURE_1trb", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[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] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1trb|  PDB=1trb  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1trb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1trb OCA], [http://www.ebi.ac.uk/pdbsum/1trb PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1trb RCSB]</span>
-}}
 '''CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES'''
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 [[Category: Krishna, T S.R.]]
 [[Category: Kuriyan, J.]]
-[[Category: oxidoreductase(flavoenzyme)]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 10:17:01 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:00:00 2008''