3EJW

Crystal Structure of the Sinorhizobium meliloti AI-2 receptor, SmLsrB


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.168 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Sinorhizobium meliloti, a bacterium lacking the autoinducer-2 (AI-2) synthase, responds to AI-2 supplied by other bacteria.

Pereira, C.S.McAuley, J.R.Taga, M.E.Xavier, K.B.Miller, S.T.

(2008) Mol.Microbiol. 70: 1223-1235

  • DOI: 10.1111/j.1365-2958.2008.06477.x

  • PubMed Abstract: 
  • Many bacterial species respond to the quorum-sensing signal autoinducer-2 (AI-2) by regulating different niche-specific genes. Here, we show that Sinorhizobium meliloti, a plant symbiont lacking the gene for the AI-2 synthase, while not capable of pr ...

    Many bacterial species respond to the quorum-sensing signal autoinducer-2 (AI-2) by regulating different niche-specific genes. Here, we show that Sinorhizobium meliloti, a plant symbiont lacking the gene for the AI-2 synthase, while not capable of producing AI-2 can nonetheless respond to AI-2 produced by other species. We demonstrate that S. meliloti has a periplasmic binding protein that binds AI-2. The crystal structure of this protein (here named SmlsrB) with its ligand reveals that it binds (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran (R-THMF), the identical AI-2 isomer recognized by LsrB of Salmonella typhimurium. The gene encoding SmlsrB is in an operon with orthologues of the lsr genes required for AI-2 internalization in enteric bacteria. Accordingly, S. meliloti internalizes exogenous AI-2, and mutants in this operon are defective in AI-2 internalization. S. meliloti does not gain a metabolic benefit from internalizing AI-2, suggesting that AI-2 functions as a signal in S. meliloti. Furthermore, S. meliloti can completely eliminate the AI-2 secreted by Erwinia carotovora, a plant pathogen shown to use AI-2 to regulate virulence. Our findings suggest that S. meliloti is capable of 'eavesdropping' on the AI-2 signalling of other species and interfering with AI-2-regulated behaviours such as virulence.


    Organizational Affiliation

    Bacterial Signaling Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SmLsrB
A, B
315Rhizobium meliloti (strain 1021)Mutation(s): 0 
Find proteins for Q926H7 (Rhizobium meliloti (strain 1021))
Go to UniProtKB:  Q926H7
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PAV
Query on PAV

Download SDF File 
Download CCD File 
A, B
(2R,4S)-2-METHYL-2,3,3,4-TETRAHYDROXYTETRAHYDROFURAN
C5 H10 O5
BVIYGXUQVXBHQS-IUYQGCFVSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.168 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 57.848α = 90.00
b = 71.488β = 98.69
c = 68.035γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
PHENIXrefinement
PHASERphasing
MOSFLMdata reduction
CrystalCleardata collection
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-12-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2018-04-04
    Type: Data collection