Biological Assembly 1  

 3D View: Structure | 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: 35.32 kDa 
• Atom Count: 2558 
• Modelled Residue Count: 317 
• Deposited Residue Count: 320 
• Unique protein chains: 1

1CL0

CRYSTAL STRUCTURE OF REDUCED THIOREDOXIN REDUCTASE FROM ESCHERICHIA COLI.

• DOI: 10.2210/pdb1CL0/pdb

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


• Deposited: 1999-05-04 Released: 1999-12-03 
• Deposition Author(s): Lennon, B.W., Williams Jr, C.H., Ludwig, M.L.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.292 
• R-Value Work: 0.200 

Literature

Crystal structure of reduced thioredoxin reductase from Escherichia coli: structural flexibility in the isoalloxazine ring of the flavin adenine dinucleotide cofactor.

Lennon, B.W., Williams Jr., C.H., Ludwig, M.L.

(1999) Protein Sci 8: 2366-2379

• PubMed: 10595539 
• DOI: 10.1110/ps.8.11.2366
• Primary Citation of Related Structures:  
  1CL0


• PubMed Abstract: 
  

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.

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Related Citations: 

• Crystal structure of Escherichia coli thioredoxin reductase refined at 2 A resolution. Implications for a large conformational change during catalysis.
  Waksman, G., Krishna, T.S., Williams Jr., C.H., Kuriyan, J.
  (1994) J Mol Biol 236: 800

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Organizational Affiliation: 

Department of Biological Chemistry, The University of Michigan, Ann Arbor 48109, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
THIOREDOXIN REDUCTASE	A	320	Escherichia coli	Mutation(s): 0  Gene Names: trxB EC: 1.6.4.5 (PDB Primary Data), 1.8.1.9 (UniProt)
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 (Subject of Investigation/LOI)	B [auth A]	FLAVIN-ADENINE DINUCLEOTIDE C27 H33 N9 O15 P2 VWWQXMAJTJZDQX-UYBVJOGSSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.292 
• R-Value Work: 0.200 
• Space Group: P 6₃ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 121.298	α = 90
b = 121.298	β = 90
c = 81.32	γ = 120

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1999-05-04 
• Released Date: 1999-12-03 
Deposition Author(s): Lennon, B.W., Williams Jr, C.H., Ludwig, M.L.

Revision History  

• Version 1.0: 1999-12-03
  Type: Initial release
  
• Version 1.1: 2008-04-26
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Derived calculations, Version format compliance
• Version 1.3: 2019-11-27
  Changes: Database references