9KME | pdb_00009kme

Crystal structure of soluble bacteriorhodopsin NeuroBR_A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free: 
    0.213 (Depositor), 0.219 (DCC) 
  • R-Value Work: 
    0.177 (Depositor), 0.187 (DCC) 
  • R-Value Observed: 
    0.179 (Depositor) 

Starting Model: in silico
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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

Engineering of soluble bacteriorhodopsin.

Nikolaev, A.Orlov, Y.Tsybrov, F.Kuznetsova, E.Shishkin, P.Kuzmin, A.Mikhailov, A.Nikolaeva, Y.S.Anuchina, A.Chizhov, I.Semenov, O.Kapranov, I.Borshchevskiy, V.Remeeva, A.Gushchin, I.

(2025) Chem Sci 16: 11067-11076

  • DOI: https://doi.org/10.1039/d5sc02453f
  • Primary Citation of Related Structures:  
    9KME

  • PubMed Abstract: 

    Studies and applications of membrane proteins remain challenging due to the requirement of maintaining them in a lipid membrane or a membrane mimic. Modern machine learning-based protein engineering methods offer a possibility of generating soluble analogs of membrane proteins that retain the active site structure and ligand-binding properties; however, clear examples are currently missing. Here, we report successful engineering of proteins dubbed NeuroBRs that mimic the active site (retinal-binding pocket) of bacteriorhodopsin, a light-driven proton pump and well-studied model membrane protein. NeuroBRs are soluble and stable, bind retinal and exhibit photocycles under illumination. The crystallographic structure of NeuroBR_A, determined at anisotropic resolution reaching 1.76 Å, reveals an excellently conserved chromophore binding pocket and tertiary structure. Thus, NeuroBRs are promising microbial rhodopsin mimics for studying retinal photochemistry and potential soluble effector modules for optogenetic tools. Overall, our results highlight the power of modern protein engineering approaches and pave the way towards wider development of molecular tools derived from membrane proteins.


  • Organizational Affiliation
    • Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology Dolgoprudny Russia ivan.gushchin@phystech.edu.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
soluble bacteriorhodopsin
A, B, C, D
237synthetic constructMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
RET
Query on RET

Download Ideal Coordinates CCD File 
E [auth A],
G [auth B],
I [auth C],
L [auth D]
RETINAL
C20 H28 O
NCYCYZXNIZJOKI-OVSJKPMPSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
F [auth A],
H [auth B],
J [auth C],
K [auth C]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free:  0.213 (Depositor), 0.219 (DCC) 
  • R-Value Work:  0.177 (Depositor), 0.187 (DCC) 
  • R-Value Observed: 0.179 (Depositor) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 95.035α = 90
b = 96.092β = 90
c = 109.93γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
STARANISOdata scaling
xia2data reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Ministry of Science and Higher Education of the Russian FederationRussian Federation075-15-2021-1354
Ministry of Science and Higher Education of the Russian FederationRussian Federation075-03-2024-117, project FSMG-2021-0002
Russian Science FoundationRussian Federation21-64-00018

Revision History  (Full details and data files)

  • Version 1.0: 2025-06-04
    Type: Initial release
  • Version 1.1: 2025-07-02
    Changes: Database references