Crystal Structure of RRSP, a MARTX Toxin Effector Domain from Vibrio vulnificus CMCP6

Experimental Data Snapshot

  • Resolution: 3.45 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.229 

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The bacterial Ras/Rap1 site-specific endopeptidase RRSP cleaves Ras through an atypical mechanism to disrupt Ras-ERK signaling.

Biancucci, M.Minasov, G.Banerjee, A.Herrera, A.Woida, P.J.Kieffer, M.B.Bindu, L.Abreu-Blanco, M.Anderson, W.F.Gaponenko, V.Stephen, A.G.Holderfield, M.Satchell, K.J.F.

(2018) Sci Signal 11

  • DOI: https://doi.org/10.1126/scisignal.aat8335
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The Ras-extracellular signal-regulated kinase pathway is critical for controlling cell proliferation, and its aberrant activation drives the growth of various cancers. Because many pathogens produce toxins that inhibit Ras activity, efforts to develop effective Ras inhibitors to treat cancer could be informed by studies of Ras inhibition by pathogens. Vibrio vulnificus causes fatal infections in a manner that depends on multifunctional autoprocessing repeats-in-toxin, a toxin that releases bacterial effector domains into host cells. One such domain is the Ras/Rap1-specific endopeptidase (RRSP), which site-specifically cleaves the Switch I domain of the small GTPases Ras and Rap1. We solved the crystal structure of RRSP and found that its backbone shares a structural fold with the EreA/ChaN-like superfamily of enzymes. Unlike other proteases in this family, RRSP is not a metalloprotease. Through nuclear magnetic resonance analysis and nucleotide exchange assays, we determined that the processing of KRAS by RRSP did not release any fragments or cause KRAS to dissociate from its bound nucleotide but instead only locally affected its structure. However, this structural alteration of KRAS was sufficient to disable guanine nucleotide exchange factor-mediated nucleotide exchange and prevent KRAS from binding to RAF. Thus, RRSP is a bacterial effector that represents a previously unrecognized class of protease that disconnects Ras from its signaling network while inducing limited structural disturbance in its target.

  • Organizational Affiliation

    Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
RTX repeat-containing cytotoxin
A, B
518Vibrio vulnificusMutation(s): 0 
Gene Names: XM78_c20952
Find proteins for A0A3B6UEL2 (Vibrio vulnificus)
Explore A0A3B6UEL2 
Go to UniProtKB:  A0A3B6UEL2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A3B6UEL2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.45 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.229 
  • Space Group: I 2 3
  • Diffraction Data: https://doi.org/10.18430/m35w6l
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 247.103α = 90
b = 247.103β = 90
c = 247.103γ = 90
Software Package:
Software NamePurpose
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2018-06-27
    Type: Initial release
  • Version 1.1: 2018-10-10
    Changes: Data collection, Database references, Structure summary