5J4M

Crystal structure of shaft pilin SpaA from Lactobacillus rhamnosus GG - E269A/D295N double mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.99 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.206 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

New insights about pilus formation in gut-adapted Lactobacillus rhamnosus GG from the crystal structure of the SpaA backbone-pilin subunit

Chaurasia, P.Pratap, S.von Ossowski, I.Palva, A.Krishnan, V.

(2016) Sci Rep 6: 28664-28664

  • DOI: https://doi.org/10.1038/srep28664
  • Primary Citation of Related Structures:  
    5F44, 5FAA, 5FGR, 5FGS, 5FIE, 5HBB, 5HDL, 5HTS, 5J4M

  • PubMed Abstract: 

    Thus far, all solved structures of pilin-proteins comprising sortase-assembled pili are from pathogenic genera and species. Here, we present the first crystal structure of a pilin subunit (SpaA) from a non-pathogen host (Lactobacillus rhamnosus GG). SpaA consists of two tandem CnaB-type domains, each with an isopeptide bond and E-box motif. Intriguingly, while the isopeptide bond in the N-terminal domain forms between lysine and asparagine, the one in the C-terminal domain atypically involves aspartate. We also solved crystal structures of mutant proteins where residues implicated in forming isopeptide bonds were replaced. Expectedly, the E-box-substituted E139A mutant lacks an isopeptide bond in the N-terminal domain. However, the C-terminal E269A substitution gave two structures; one of both domains with their isopeptide bonds present, and another of only the N-terminal domain, but with an unformed isopeptide bond and significant conformational changes. This latter crystal structure has never been observed for any other Gram-positive pilin. Notably, the C-terminal isopeptide bond still forms in D295N-substituted SpaA, irrespective of E269 being present or absent. Although E-box mutations affect SpaA proteolytic and thermal stability, a cumulative effect perturbing normal pilus polymerization was unobserved. A model showing the polymerized arrangement of SpaA within the SpaCBA pilus is proposed.


  • Organizational Affiliation

    Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-121 001, India.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cell surface protein SpaA
A, B, C
283Lacticaseibacillus rhamnosus GGMutation(s): 2 
Gene Names: LRHM_0426
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.99 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.206 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 229.7α = 90
b = 64.394β = 95.44
c = 105.049γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata processing
MOLREPphasing
Cootmodel building
Aimlessdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Department of BiotechnologyIndiaBT/PR5891/BRB/10/1098/2012

Revision History  (Full details and data files)

  • Version 1.0: 2016-07-20
    Type: Initial release
  • Version 1.1: 2023-11-08
    Changes: Data collection, Database references, Derived calculations, Refinement description