Crystal structure of the GP2 Core Domain from the California Academy of Science Virus

Experimental Data Snapshot

  • Resolution: 1.99 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.170 

Starting Model: experimental
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Structural Characterization of the Glycoprotein GP2 Core Domain from the CAS Virus, a Novel Arenavirus-Like Species.

Koellhoffer, J.F.Dai, Z.Malashkevich, V.N.Stenglein, M.D.Liu, Y.Toro, R.S Harrison, J.Chandran, K.Derisi, J.L.Almo, S.C.Lai, J.R.

(2014) J Mol Biol 426: 1452-1468

  • DOI: https://doi.org/10.1016/j.jmb.2013.12.009
  • Primary Citation of Related Structures:  
    4N21, 4N23

  • PubMed Abstract: 

    Fusion of the viral and host cell membranes is a necessary first step for infection by enveloped viruses and is mediated by the envelope glycoprotein. The transmembrane subunits from the structurally defined "class I" glycoproteins adopt an α-helical "trimer-of-hairpins" conformation during the fusion pathway. Here, we present our studies on the envelope glycoprotein transmembrane subunit, GP2, of the CAS virus (CASV). CASV was recently identified from annulated tree boas (Corallus annulatus) with inclusion body disease and is implicated in the disease etiology. We have generated and characterized two protein constructs consisting of the predicted CASV GP2 core domain. The crystal structure of the CASV GP2 post-fusion conformation indicates a trimeric α-helical bundle that is highly similar to those of Ebola virus and Marburg virus GP2 despite CASV genome homology to arenaviruses. Denaturation studies demonstrate that the stability of CASV GP2 is pH dependent with higher stability at lower pH; we propose that this behavior is due to a network of interactions among acidic residues that would destabilize the α-helical bundle under conditions where the side chains are deprotonated. The pH-dependent stability of the post-fusion structure has been observed in Ebola virus and Marburg virus GP2, as well as other viruses that enter via the endosome. Infection experiments with CASV and the related Golden Gate virus support a mechanism of entry that requires endosomal acidification. Our results suggest that, despite being primarily arenavirus like, the transmembrane subunit of CASV is extremely similar to the filoviruses.

  • Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GP2 Ectodomain
A, B, C, D, E
A, B, C, D, E, F
130CAS virusMutation(s): 0 
Gene Names: GP2
Find proteins for J7H5L9 (CAS virus)
Explore J7H5L9 
Go to UniProtKB:  J7H5L9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupJ7H5L9
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on MPD

Download Ideal Coordinates CCD File 
G [auth A]
H [auth A]
I [auth B]
J [auth B]
K [auth B]
G [auth A],
H [auth A],
I [auth B],
J [auth B],
K [auth B],
L [auth C],
M [auth C],
N [auth D],
O [auth D],
P [auth E],
Q [auth E]
C6 H14 O2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.99 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.170 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.676α = 102.32
b = 46.713β = 89.99
c = 109.451γ = 119.98
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-3000data reduction

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2014-01-08
    Changes: Database references
  • Version 1.2: 2014-04-02
    Changes: Database references
  • Version 1.3: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description