1M0L

BACTERIORHODOPSIN/LIPID COMPLEX AT 1.47 A RESOLUTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.47 Å
  • R-Value Free: 0.179 
  • R-Value Work: 0.149 
  • R-Value Observed: 0.149 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

Crystallographic structure of the K intermediate of bacteriorhodopsin: conservation of free energy after photoisomerization of the retinal.

Schobert, B.Cupp-Vickery, J.Hornak, V.Smith, S.Lanyi, J.

(2002) J Mol Biol 321: 715-726

  • DOI: https://doi.org/10.1016/s0022-2836(02)00681-2
  • Primary Citation of Related Structures:  
    1M0K, 1M0L

  • PubMed Abstract: 

    The K state, an early intermediate of the bacteriorhodopsin photocycle, contains the excess free energy used for light-driven proton transport. The energy gain must reside in or near the photoisomerized retinal, but in what form has long been an open question. We produced the K intermediate in bacteriorhodopsin crystals in a photostationary state at 100K, with 40% yield, and determined its X-ray diffraction structure to 1.43 A resolution. In independent refinements of data from four crystals, the changes are confined mainly to the photoisomerized retinal. The retinal is 13-cis,15-anti, as known from vibrational spectroscopy. The C13=C14 bond is rotated nearly fully to cis from the initial trans configuration, but the C14-C15 and C15=NZ bonds are partially counter-rotated. This strained geometry keeps the direction of the Schiff base N-H bond vector roughly in the extracellular direction, but the angle of its hydrogen bond with water 402, that connects it to the anionic Asp85 and Asp212, is not optimal. Weakening of this hydrogen bond may account for many of the reported features of the infrared spectrum of K, and for its photoelectric signal, as well as the deprotonation of the Schiff base later in the cycle. Importantly, although 13-cis, the retinal does not assume the expected bent shape of this configuration. Comparison of the calculated energy of the increased angle of C12-C13=C14, that allows this distortion, with the earlier reported calorimetric measurement of the enthalpy gain of the K state indicates that a significant part of the excess energy is conserved in the bond strain at C13.


  • Organizational Affiliation

    Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BACTERIORHODOPSIN262Halobacterium salinarumMutation(s): 0 
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 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
LI1
Query on LI1

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

Download Ideal Coordinates CCD File 
O [auth A]2,10,23-TRIMETHYL-TETRACOSANE
C27 H56
ZADHKSJXSZBQFB-HHHXNRCGSA-N
RET
Query on RET

Download Ideal Coordinates CCD File 
P [auth A]RETINAL
C20 H28 O
NCYCYZXNIZJOKI-OVSJKPMPSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.47 Å
  • R-Value Free: 0.179 
  • R-Value Work: 0.149 
  • R-Value Observed: 0.149 
  • Space Group: P 63
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.94α = 90
b = 60.94β = 90
c = 110.55γ = 120
Software Package:
Software NamePurpose
SHELXmodel building
SHELXL-97refinement
DENZOdata reduction
SCALEPACKdata scaling
SHELXphasing

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2002-09-11 
  • Deposition Author(s): Lanyi, J.K.

Revision History  (Full details and data files)

  • Version 1.0: 2002-09-11
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2024-11-06
    Changes: Data collection, Database references, Derived calculations, Refinement description, Structure summary