Biological Assembly 1  

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Hetero 4-mer - A2B2 

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

Biological Assembly 2  

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Hetero 4-mer - A2B2 

Biological assembly 2 assigned by authors and generated by PISA (software)

Biological Assembly 3  

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Hetero 4-mer - A2B2 

Biological assembly 3 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 455.26 kDa 
• Atom Count: 30,609 
• Modelled Residue Count: 3,900 
• Deposited Residue Count: 4,080 
• Unique protein chains: 2

 4AAY

Crystal Structure of the arsenite oxidase protein complex from Rhizobium species strain NT-26

• PDB DOI:  https://doi.org/10.2210/pdb4AAY/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Pseudorhizobium banfieldiae
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2011-12-05 Released: 2012-12-12 
• Deposition Author(s): Oke, M., Santini, J.M., Naismith, J.H.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free: 0.211 
• R-Value Work: 0.193 
• R-Value Observed: 0.194 

Literature

The Respiratory Arsenite Oxidase: Structure and the Role of Residues Surrounding the Rieske Cluster.

Warelow, T.P., Oke, M., Schoepp-Cothenet, B., Dahl, J.U., Bruselat, N., Sivalingam, G.N., Leimkuhler, S., Thalassinos, K., Kappler, U., Naismith, J.H., Santini, J.M.

(2013) PLoS One 8: 72535

• PubMed: 24023621 
• DOI: https://doi.org/10.1371/journal.pone.0072535
• Primary Citation of Related Structures:  
  4AAY


• PubMed Abstract: 
  

The arsenite oxidase (Aio) from the facultative autotrophic Alphaproteobacterium Rhizobium sp. NT-26 is a bioenergetic enzyme involved in the oxidation of arsenite to arsenate. The enzyme from the distantly related heterotroph, Alcaligenes faecalis, which is thought to oxidise arsenite for detoxification, consists of a large α subunit (AioA) with bis-molybdopterin guanine dinucleotide at its active site and a 3Fe-4S cluster, and a small β subunit (AioB) which contains a Rieske 2Fe-2S cluster. The successful heterologous expression of the NT-26 Aio in Escherichia coli has resulted in the solution of its crystal structure. The NT-26 Aio, a heterotetramer, shares high overall similarity to the heterodimeric arsenite oxidase from A. faecalis but there are striking differences in the structure surrounding the Rieske 2Fe-2S cluster which we demonstrate explains the difference in the observed redox potentials (+225 mV vs. +130/160 mV, respectively). A combination of site-directed mutagenesis and electron paramagnetic resonance was used to explore the differences observed in the structure and redox properties of the Rieske cluster. In the NT-26 AioB the substitution of a serine (S126 in NT-26) for a threonine as in the A. faecalis AioB explains a -20 mV decrease in redox potential. The disulphide bridge in the A. faecalis AioB which is conserved in other betaproteobacterial AioB subunits and the Rieske subunit of the cytochrome bc 1 complex is absent in the NT-26 AioB subunit. The introduction of a disulphide bridge had no effect on Aio activity or protein stability but resulted in a decrease in the redox potential of the cluster. These results are in conflict with previous data on the betaproteobacterial AioB subunit and the Rieske of the bc 1 complex where removal of the disulphide bridge had no effect on the redox potential of the former but a decrease in cluster stability was observed in the latter.

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Organizational Affiliation: 

Institute of Structural and Molecular Biology, University College London, London, United Kingdom.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
AROA	A, C, E, G	845	Pseudorhizobium banfieldiae	Mutation(s): 0  Gene Names: aroA, aioA, NT26_p10030 EC: 1.20.98.1
UniProt
Find proteins for Q6VAL8 (Pseudorhizobium banfieldiae) Explore Q6VAL8  Go to UniProtKB:  Q6VAL8

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
AROB	B, D, F, H	175	Pseudorhizobium banfieldiae	Mutation(s): 0  Gene Names: aroB
UniProt
Find proteins for Q6VAL9 (Pseudorhizobium banfieldiae) Explore Q6VAL9  Go to UniProtKB:  Q6VAL9

Small Molecules

Ligands 5 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
MGD	AA [auth G], BA [auth G], I [auth A], J [auth A], O [auth C], P [auth C], U [auth E], V [auth E]	2-AMINO-5,6-DIMERCAPTO-7-METHYL-3,7,8A,9-TETRAHYDRO-8-OXA-1,3,9,10-TETRAAZA-ANTHRACEN-4-ONE GUANOSINE DINUCLEOTIDE C20 H26 N10 O13 P2 S2 VQAGYJCYOLHZDH-ILXWUORBSA-N
F3S	EA [auth G], M [auth A], S [auth C], Y [auth E]	FE3-S4 CLUSTER Fe3 S4 FCXHZBQOKRZXKS-MZMDZPPWAW
FES	FA [auth H], N [auth B], T [auth D], Z [auth F]	FE2/S2 (INORGANIC) CLUSTER Fe2 S2 NIXDOXVAJZFRNF-UHFFFAOYSA-N
4MO	DA [auth G], L [auth A], R [auth C], X [auth E]	MOLYBDENUM(IV) ION Mo ZIKKVZAYJJZBGE-UHFFFAOYSA-N
O	CA [auth G], K [auth A], Q [auth C], W [auth E]	OXYGEN ATOM O XLYOFNOQVPJJNP-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free: 0.211 
• R-Value Work: 0.193 
• R-Value Observed: 0.194 
• Space Group: P 2₁ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 149.13	α = 90
b = 232.96	β = 90
c = 141.87	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
xia2	data reduction
xia2	data scaling
PHASER	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2012-12-12 
Deposition Author(s): Oke, M., Santini, J.M., Naismith, J.H.

Revision History  

• Version 1.0: 2012-12-12
  Type: Initial release
  
• Version 1.1: 2013-09-25
  Changes: Database references
• Version 1.2: 2013-11-20
  Changes: Derived calculations, Refinement description
• Version 1.3: 2014-03-12
  Changes: Source and taxonomy