5Z3J

Crystal Structure of Abrin A chain (Recombinant) in complex with Nicotinamide at 1.7 Angstroms


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.201 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Structural basis for neutralization of cytotoxic abrin by monoclonal antibody D6F10.

Bansia, H.Bagaria, S.Karande, A.A.Ramakumar, S.

(2019) FEBS J 286: 1003-1029

  • DOI: 10.1111/febs.14716
  • Primary Citation of Related Structures:  
    5Z3I, 5Z3J, 5Z37

  • PubMed Abstract: 
  • Abrin, an extremely cytotoxic Type II ribosome-inactivating protein (RIP), is a potential bio-warfare agent. Abrin A-chain (ABA) depurinates an adenosine of sarcin-ricin loop (SRL) from eukaryotic 28S rRNA, thereby arresting protein synthesis and leading to cell death ...

    Abrin, an extremely cytotoxic Type II ribosome-inactivating protein (RIP), is a potential bio-warfare agent. Abrin A-chain (ABA) depurinates an adenosine of sarcin-ricin loop (SRL) from eukaryotic 28S rRNA, thereby arresting protein synthesis and leading to cell death. Monoclonal antibody (mAb) D6F10 is the only known antibody that neutralizes ABA's activity in cell-free systems as well as abrin's toxicity in vitro and in vivo. However, how binding of mAb D6F10 to abrin interferes with abrin's catalytic activity at ribosome is still poorly understood. To provide structural basis for mAb D6F10-mediated rescue of ribosome inactivation by abrin, we determined crystal structures of ABA with and without substrate analogs. The structures of ABA-substrate analogs and ribosome were used in an experiment-guided computational protocol, to construct the ABA-Ribosome complex. A homology model of the variable region (F v ) of mAb D6F10 was generated and docked with the apo-ABA structure to construct the ABA-D6F10 F v complex. Structural superposition of ABA common to ABA-D6F10 F v and ABA-Ribosome complexes reveals steric hindrance as the primary mechanism by which mAb D6F10 neutralizes abrin. In contrast to ABA alone, ABA bound to mAb D6F10 is unable to access the SRL on the ribosome owing to steric clashes of mAb D6F10 with the ribosome. Crystal structures of ABA also reveal a catalytic water molecule implicated in hydrolyzing N-glycosidic bond of the susceptible adenosine by RIPs. Furthermore, our strategy provides structural details of steric hindrance important for neutralization of ricin, another RIP, by mAb 6C2 and hence is of wide applicability. ENZYME: EC3.2.2.22. DATABASE: Structural data have been deposited in the Protein Data Bank (PDB) under the accession numbers 5Z37, 5Z3I, and 5Z3J.


    Organizational Affiliation

    Department of Physics, Indian Institute of Science, Bengaluru, India.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Abrin A-chainA265Abrus precatoriusMutation(s): 0 
EC: 3.2.2.22
UniProt
Find proteins for P11140 (Abrus precatorius)
Explore P11140 
Go to UniProtKB:  P11140
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NCA
Query on NCA

Download Ideal Coordinates CCD File 
C [auth A]NICOTINAMIDE
C6 H6 N2 O
DFPAKSUCGFBDDF-UHFFFAOYSA-N
 Ligand Interaction
IMD
Query on IMD

Download Ideal Coordinates CCD File 
B [auth A]IMIDAZOLE
C3 H5 N2
RAXXELZNTBOGNW-UHFFFAOYSA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.201 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.66α = 90
b = 74.08β = 90
c = 82.48γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
Aimlessdata scaling
PDB_EXTRACTdata extraction
MOSFLMdata reduction
PHASERphasing

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-01-02
    Type: Initial release
  • Version 1.1: 2019-03-20
    Changes: Data collection, Database references