3T45

Crystal structure of bacteriorhodopsin mutant A215T, a phototaxis signaling mutant at 3.0 A resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.01 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.240 

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Ligand Structure Quality Assessment 


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Literature

A transporter converted into a sensor, a phototaxis signaling mutant of bacteriorhodopsin at 3.0 angstrom.

Spudich, E.N.Ozorowski, G.Schow, E.V.Tobias, D.J.Spudich, J.L.Luecke, H.

(2012) J Mol Biol 415: 455-463

  • DOI: https://doi.org/10.1016/j.jmb.2011.11.025
  • Primary Citation of Related Structures:  
    3T45

  • PubMed Abstract: 

    Bacteriorhodopsin (BR) and sensory rhodopsin II (SRII), homologous photoactive proteins in haloarchaea, have different molecular functions. BR is a light-driven proton pump, whereas SRII is a phototaxis receptor that transmits a light-induced conformational change to its transducer HtrII. Despite these distinctly different functions, a single residue substitution, Ala215 to Thr215 in the BR retinal-binding pocket, enables its photochemical reactions to transmit signals to HtrII and mediate phototaxis. We pursued a crystal structure of the signaling BR mutant (BR_A215T) to determine the structural changes caused by the A215T mutation and to assess what new photochemistry is likely to be introduced into the BR photoactive site. We crystallized BR_A215T from bicelles and solved its structure to 3.0 Å resolution to enable an atomic-level comparison. The analysis was complemented by molecular dynamics simulation of BR mutated in silico. Three main conclusions regarding the roles of photoactive site residues in signaling emerge from the comparison of BR_A215T, BR, and SRII structures: (i) the Thr215 residue in signaling BR is positioned nearly identically with respect to the retinal chromophore as in SRII, consistent with its role in producing a steric conflict with the retinal C₁₄ group during photoisomerization, proposed earlier to be essential for SRII signaling from vibrational spectroscopy and motility measurements; (ii) Tyr174-Thr204 hydrogen bonding, critical in SRII signaling and mimicked in signaling BR, is likely auxiliary, for example, to maintain Thr204 in the proper position for the steric trigger to occur; and (iii) the primary role of Arg72 in SRII is spectral tuning and not signaling.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Medical School, Houston, TX 77030, USA. john.l.spudich@uth.tmc.edu


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Bacteriorhodopsin (GROUND STATE)
A, B, C
225Halobacterium salinarum NRC-1Mutation(s): 1 
Gene Names: bopVNG_1467G
Membrane Entity: Yes 
UniProt
Find proteins for P02945 (Halobacterium salinarum (strain ATCC 700922 / JCM 11081 / NRC-1))
Explore P02945 
Go to UniProtKB:  P02945
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02945
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
LI1
Query on LI1

Download Ideal Coordinates CCD File 
E [auth A]
F [auth A]
H [auth B]
I [auth B]
J [auth B]
E [auth A],
F [auth A],
H [auth B],
I [auth B],
J [auth B],
K [auth B],
L [auth B],
M [auth B],
N [auth B],
P [auth C],
Q [auth C]
1-[2,6,10.14-TETRAMETHYL-HEXADECAN-16-YL]-2-[2,10,14-TRIMETHYLHEXADECAN-16-YL]GLYCEROL
C42 H86 O3
YERVUJAKCNBGCR-BIHSMRAKSA-N
RET
Query on RET

Download Ideal Coordinates CCD File 
D [auth A],
G [auth B],
O [auth C]
RETINAL
C20 H28 O
NCYCYZXNIZJOKI-OVSJKPMPSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.01 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.240 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.452α = 90
b = 106.139β = 95.08
c = 124.845γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-12-21
    Type: Initial release
  • Version 1.1: 2013-09-04
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Refinement description