6L1Q

Crystal structure of AfCbbQ2, a MoxR AAA+-ATPase and CbbQO-type Rubisco activase from Acidithiobacillus ferrooxidans


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.197 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase.

Tsai, Y.C.Ye, F.Liew, L.Liu, D.Bhushan, S.Gao, Y.G.Mueller-Cajar, O.

(2020) Proc Natl Acad Sci U S A 117: 381-387

  • DOI: 10.1073/pnas.1911123117
  • Primary Citation of Related Structures:  
    6L1Q

  • PubMed Abstract: 
  • The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates ...

    The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates. The inhibition is counteracted by diverse molecular chaperones known as Rubisco activases (Rcas). In some chemoautotrophic bacteria, the CbbQO-type Rca Q2O2 repairs inhibited active sites of hexameric form II Rubisco. The 2.2-Å crystal structure of the MoxR AAA+ protein CbbQ2 from Acidithiobacillus ferrooxidans reveals the helix 2 insert (H2I) that is critical for Rca function and forms the axial pore of the CbbQ hexamer. Negative-stain electron microscopy shows that the essential CbbO adaptor protein binds to the conserved, concave side of the CbbQ2 hexamer. Site-directed mutagenesis supports a model in which adenosine 5'-triphosphate (ATP)-powered movements of the H2I are transmitted to CbbO via the concave residue L85. The basal ATPase activity of Q2O2 Rca is repressed but strongly stimulated by inhibited Rubisco. The characterization of multiple variants where this repression is released indicates that binding of inhibited Rubisco to the C-terminal CbbO VWA domain initiates a signal toward the CbbQ active site that is propagated via elements that include the CbbQ α4-β4 loop, pore loop 1, and the presensor 1-β hairpin (PS1-βH). Detailed mechanistic insights into the enzyme repair chaperones of the highly diverse CO 2 fixation machinery of Proteobacteria will facilitate their successful implementation in synthetic biology ventures.


    Organizational Affiliation

    Nanyang Technological University Institute of Structural Biology, Nanyang Technological University, 636921, Singapore.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CbbQ proteinB [auth A],
C [auth B],
A [auth C]
380Acidithiobacillus ferrooxidans ATCC 23270Mutation(s): 0 
Gene Names: cbbQ-2AFE_2156
UniProt
Find proteins for B7J5E4 (Acidithiobacillus ferrooxidans (strain ATCC 23270 / DSM 14882 / CIP 104768 / NCIMB 8455))
Explore B7J5E4 
Go to UniProtKB:  B7J5E4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB7J5E4
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.197 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 167.753α = 90
b = 167.753β = 90
c = 48.291γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Ministry of Education (Singapore)SingaporeMOE2016-T2-02-088

Revision History  (Full details and data files)

  • Version 1.0: 2019-12-18
    Type: Initial release
  • Version 1.1: 2020-01-01
    Changes: Database references
  • Version 1.2: 2020-01-22
    Changes: Database references