Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA,PQS (software)

Macromolecule Content

• Total Structure Weight: 35.30 kDa 
• Atom Count: 2611 
• Modelled Residue Count: 316 
• Deposited Residue Count: 320 
• Unique protein chains: 1

1TRB

CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN TWO STRUCTURALLY DIVERGENT ENZYMES

• DOI: 10.2210/pdb1TRB/pdb

• Classification: OXIDOREDUCTASE(FLAVOENZYME)
• Organism(s): Escherichia coli
• Mutation(s): No 


• Deposited: 1991-09-07 Released: 1994-01-31 
• Deposition Author(s): Kuriyan, J., Krishna, T.S.R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Work: 0.177 
• R-Value Observed: 0.177 

Literature

Convergent evolution of similar function in two structurally divergent enzymes.

Kuriyan, J., Krishna, T.S., Wong, L., Guenther, B., Pahler, A., Williams Jr., C.H., Model, P.

(1991) Nature 352: 172-174

• PubMed: 2067578 
• DOI: 10.1038/352172a0
• Primary Citation of Related Structures:  
  1TRB


• PubMed Abstract: 
  

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.

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Related Citations: 

• Crystallization and Preliminary X-Ray Characterization of Thioredoxin Reductase from Escherichia Coli
  Kuriyan, J., Wong, L., Russel, M., Model, P.
  (1989) J Biol Chem 264: 12752

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Organizational Affiliation: 

Rockefeller University, New York 10021.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
THIOREDOXIN REDUCTASE	A	320	Escherichia coli	Mutation(s): 0  EC: 1.6.4.5 (PDB Primary Data), 1.8.1.9 (UniProt)
Find proteins for P0A9P4 (Escherichia coli (strain K12)) Explore P0A9P4  Go to UniProtKB:  P0A9P4

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
FAD	B [auth A]	FLAVIN-ADENINE DINUCLEOTIDE C27 H33 N9 O15 P2 VWWQXMAJTJZDQX-UYBVJOGSSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Work: 0.177 
• R-Value Observed: 0.177 
• Space Group: P 6₃ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 123.1	α = 90
b = 123.1	β = 90
c = 81.4	γ = 120

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1991-09-07 
• Released Date: 1994-01-31 
Deposition Author(s): Kuriyan, J., Krishna, T.S.R.

Revision History  

• Version 1.0: 1994-01-31
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Derived calculations, Version format compliance