3N5B

The complex of PII and PipX from Anabaena


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.200 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Crystal structure of the cyanobacterial signal transduction protein PII in complex with PipX.

Zhao, M.-X.Jiang, Y.-L.Xu, B.-Y.Chen, Y.-X.Zhang, C.-C.Zhou, C.-Z.

(2010) J Mol Biol 402: 552-559

  • DOI: 10.1016/j.jmb.2010.08.006
  • Primary Citation of Related Structures:  
    3N5B

  • PubMed Abstract: 
  • P(II) proteins are highly conserved signal transducers in bacteria, archaea, and plants. They have a large flexible loop (T-loop) that adopts different conformations after covalent modification or binding to different effectors to regulate the functions of diverse protein partners ...

    P(II) proteins are highly conserved signal transducers in bacteria, archaea, and plants. They have a large flexible loop (T-loop) that adopts different conformations after covalent modification or binding to different effectors to regulate the functions of diverse protein partners. The P(II) partner PipX (P(II)interaction protein X), first identified from Synechococcus sp. PCC 7942, exists uniquely in cyanobacteria. PipX also interacts with the cyanobacterial global nitrogen regulator NtcA. The mutually exclusive binding of P(II) and NtcA by PipX in a 2-oxoglutarate (2-OG)-dependent manner enables P(II) to indirectly regulate the transcriptional activity of NtcA. However, the structural basis for these exclusive interactions remains unknown. We solved the crystal structure of the P(II)-PipX complex from the filamentous cyanobacterium Anabaena sp. PCC 7120 at 1.90 Å resolution. A homotrimeric P(II) captures three subunits of PipX through the T-loops. Similar to P(II) from Synechococcus, the core structure consists of an antiparallel β-sheet with four β-strands and two α-helices at the lateral surface. PipX adopts a novel structure composed of five twisted antiparallel β-strands and two α-helices, which is reminiscent of the P(II) structure. The T-loop of each P(II) subunit extends from the core structure as an antenna that is stabilized at the cleft between two PipX monomers via hydrogen bonds. In addition, the interfaces between the β-sheets of PipX and P(II) core structures partially contribute to complex formation. Comparative structural analysis indicated that PipX and 2-OG share a common binding site that overlaps with the 14 signature residues of cyanobacterial P(II) proteins. Our structure of PipX and the recently solved NtcA structure enabled us to propose a putative model for the NtcA-PipX complex. Taken together, these findings provide structural insights into how P(II) regulates the transcriptional activity of NtcA via PipX upon accumulation of the metabolite 2-OG.


    Organizational Affiliation

    Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Nitrogen regulatory protein P-IIA112Nostoc sp. PCC 7120 = FACHB-418Mutation(s): 0 
Gene Names: all2319glnB
Find proteins for Q9L422 (Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576))
Explore Q9L422 
Go to UniProtKB:  Q9L422
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Asr0485 proteinB112Nostoc sp. PCC 7120 = FACHB-418Mutation(s): 0 
Gene Names: asr0485
Find proteins for Q8YZH5 (Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576))
Explore Q8YZH5 
Go to UniProtKB:  Q8YZH5
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ADP
Query on ADP

Download Ideal Coordinates CCD File 
C [auth A]ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
D [auth B], E [auth B]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.200 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.645α = 90
b = 70.645β = 90
c = 88.544γ = 120
Software Package:
Software NamePurpose
MAR345dtbdata collection
MOLREPphasing
REFMACrefinement
HKL-2000data reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-09-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance