Crystal structure of the cyanobacterial heme-protein Tll0287

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.179 

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Crystal structure and redox properties of a novel cyanobacterial heme protein with a His/Cys heme axial ligation and a Per-Arnt-Sim (PAS)-like domain

Motomura, T.Suga, M.Hienerwadel, R.Nakagawa, A.Lai, T.L.Nitschke, W.Kuma, T.Sugiura, M.Boussac, A.Shen, J.R.

(2017) J Biol Chem 292: 9599-9612

  • DOI: https://doi.org/10.1074/jbc.M116.746263
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Photosystem II catalyzes light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The Photosystem II reaction center is composed of D1 and D2 proteins encoded by psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains three psbA genes: psbA1 , psbA2 , and psbA3 , and a new c -type heme protein, Tll0287, was found to be expressed in a strain expressing the psbA2 gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a Per-Arnt-Sim-like domain rather than to other c -type cytochromes. The fifth and sixth axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the c -type hemes. The redox potential, E ½ , of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E ½ increased by ≈57 mV/pH unit at 15 °C, suggesting the involvement of a protonatable group with a p K red = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under microaerobic conditions or a cytochrome subunit of an H 2 S-oxidizing system are discussed in view of the environmental conditions in which psbA2 is expressed, as well as phylogenetic analysis, structural, and sequence homologies.

  • Organizational Affiliation

    From the Department of Picobiology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tll0287 protein191Thermosynechococcus vestitus BP-1Mutation(s): 0 
Find proteins for Q8DM36 (Thermosynechococcus vestitus (strain NIES-2133 / IAM M-273 / BP-1))
Explore Q8DM36 
Go to UniProtKB:  Q8DM36
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8DM36
Sequence Annotations
  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.179 
  • Space Group: P 42 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 101.246α = 90
b = 101.246β = 90
c = 33.076γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number

Revision History  (Full details and data files)

  • Version 1.0: 2017-05-03
    Type: Initial release
  • Version 1.1: 2017-06-21
    Changes: Database references