6GAK

Crystal structure of the T1L reovirus sigma1 coiled coil tail (chloride)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.43 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.186 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural and Functional Features of the Reovirus sigma 1 Tail.

Dietrich, M.H.Ogden, K.M.Long, J.M.Ebenhoch, R.Thor, A.Dermody, T.S.Stehle, T.

(2018) J Virol 92

  • DOI: 10.1128/JVI.00336-18
  • Primary Citation of Related Structures:  
    6GAK, 6GAJ, 6GAO, 6GAP

  • PubMed Abstract: 
  • Mammalian orthoreovirus attachment to target cells is mediated by the outer capsid protein σ1, which projects from the virion surface. The σ1 protein is a homotrimer consisting of a filamentous tail, which is partly inserted into the virion; a body domain constructed from β-spiral repeats; and a globular head with receptor-binding properties ...

    Mammalian orthoreovirus attachment to target cells is mediated by the outer capsid protein σ1, which projects from the virion surface. The σ1 protein is a homotrimer consisting of a filamentous tail, which is partly inserted into the virion; a body domain constructed from β-spiral repeats; and a globular head with receptor-binding properties. The σ1 tail is predicted to form an α-helical coiled coil. Although σ1 undergoes a conformational change during cell entry, the nature of this change and its contributions to viral replication are unknown. Electron micrographs of σ1 molecules released from virions identified three regions of flexibility, including one at the midpoint of the molecule, that may be involved in its structural rearrangement. To enable a detailed understanding of essential σ1 tail organization and properties, we determined high-resolution structures of the reovirus type 1 Lang (T1L) and type 3 Dearing (T3D) σ1 tail domains. Both molecules feature extended α-helical coiled coils, with T1L σ1 harboring central chloride ions. Each molecule displays a discontinuity (stutter) within the coiled coil and an unexpectedly seamless transition to the body domain. The transition region features conserved interdomain interactions and appears rigid rather than highly flexible. Functional analyses of reoviruses containing engineered σ1 mutations suggest that conserved residues predicted to stabilize the coiled-coil-to-body junction are essential for σ1 folding and encapsidation, whereas central chloride ion coordination and the stutter are dispensable for efficient replication. Together, these findings enable modeling of full-length reovirus σ1 and provide insight into the stabilization of a multidomain virus attachment protein. IMPORTANCE While it is established that different conformational states of attachment proteins of enveloped viruses mediate receptor binding and membrane fusion, less is understood about how such proteins mediate attachment and entry of nonenveloped viruses. The filamentous reovirus attachment protein σ1 binds cellular receptors; contains regions of predicted flexibility, including one at the fiber midpoint; and undergoes a conformational change during cell entry. Neither the nature of the structural change nor its contribution to viral infection is understood. We determined crystal structures of large σ1 fragments for two different reovirus serotypes. We observed an unexpectedly tight transition between two domains spanning the fiber midpoint, which allows for little flexibility. Studies of reoviruses with engineered changes near the σ1 midpoint suggest that the stabilization of this region is critical for function. Together with a previously determined structure, we now have a complete model of the full-length, elongated reovirus σ1 attachment protein.


    Organizational Affiliation

    Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Outer capsid protein sigma-1A, B, C133Mammalian orthoreovirus 1 LangMutation(s): 0 
Gene Names: S1
UniProt
Find proteins for P04506 (Reovirus type 1 (strain Lang))
Explore P04506 
Go to UniProtKB:  P04506
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CL
Query on CL

Download Ideal Coordinates CCD File 
D [auth A], E [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.43 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.186 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.37α = 90
b = 37.19β = 102.66
c = 94.94γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesR01 AI118887

Revision History  (Full details and data files)

  • Version 1.0: 2018-04-25
    Type: Initial release
  • Version 1.1: 2018-05-09
    Changes: Data collection, Database references
  • Version 1.2: 2018-07-11
    Changes: Data collection, Database references