3HZQ

Structure of a tetrameric MscL in an expanded intermediate state


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.82 Å
  • R-Value Free: 0.312 
  • R-Value Work: 0.292 
  • R-Value Observed: 0.292 

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This is version 1.3 of the entry. See complete history


Literature

Structure of a tetrameric MscL in an expanded intermediate state.

Liu, Z.Gandhi, C.S.Rees, D.C.

(2009) Nature 461: 120-124

  • DOI: 10.1038/nature08277
  • Primary Citation of Related Structures:  
    3HZQ

  • PubMed Abstract: 
  • The ability of cells to sense and respond to mechanical force underlies diverse processes such as touch and hearing in animals, gravitropism in plants, and bacterial osmoregulation. In bacteria, mechanosensation is mediated by the mechanosensitive channels of large (MscL), small (MscS), potassium-dependent (MscK) and mini (MscM) conductances ...

    The ability of cells to sense and respond to mechanical force underlies diverse processes such as touch and hearing in animals, gravitropism in plants, and bacterial osmoregulation. In bacteria, mechanosensation is mediated by the mechanosensitive channels of large (MscL), small (MscS), potassium-dependent (MscK) and mini (MscM) conductances. These channels act as 'emergency relief valves' protecting bacteria from lysis upon acute osmotic down-shock. Among them, MscL has been intensively studied since the original identification and characterization 15 years ago. MscL is reversibly and directly gated by changes in membrane tension. In the open state, MscL forms a non-selective 3 nS conductance channel which gates at tensions close to the lytic limit of the bacterial membrane. An earlier crystal structure at 3.5 A resolution of a pentameric MscL from Mycobacterium tuberculosis represents a closed-state or non-conducting conformation. MscL has a complex gating behaviour; it exhibits several intermediates between the closed and open states, including one putative non-conductive expanded state and at least three sub-conducting states. Although our understanding of the closed and open states of MscL has been increasing, little is known about the structures of the intermediate states despite their importance in elucidating the complete gating process of MscL. Here we present the crystal structure of a carboxy-terminal truncation mutant (Delta95-120) of MscL from Staphylococcus aureus (SaMscL(CDelta26)) at 3.8 A resolution. Notably, SaMscL(CDelta26) forms a tetrameric channel with both transmembrane helices tilted away from the membrane normal at angles close to that inferred for the open state, probably corresponding to a non-conductive but partially expanded intermediate state.


    Organizational Affiliation

    Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Large-conductance mechanosensitive channelA114Staphylococcus aureus subsp. aureus MW2Mutation(s): 1 
Gene Names: mscLMW1235
Membrane Entity: Yes 
UniProt
Find proteins for P68806 (Staphylococcus aureus (strain MW2))
Explore P68806 
Go to UniProtKB:  P68806
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.82 Å
  • R-Value Free: 0.312 
  • R-Value Work: 0.292 
  • R-Value Observed: 0.292 
  • Space Group: I 4 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 138.589α = 90
b = 138.589β = 90
c = 138.589γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SHELXCDphasing
SHELXEmodel building
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-08-25
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 1.3: 2021-10-13
    Changes: Database references