3HIW

Crystal structure of Saporin-L1 in complex with the cyclic tetranucleotide inhibitor, a transition state analogue


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.184 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Transition state analogues in structures of ricin and saporin ribosome-inactivating proteins.

Ho, M.C.Sturm, M.B.Almo, S.C.Schramm, V.L.

(2009) Proc Natl Acad Sci U S A 106: 20276-20281

  • DOI: 10.1073/pnas.0911606106
  • Primary Citation of Related Structures:  
    3HIO, 3HIQ, 3HIS, 3HIT, 3HIV, 3HIW

  • PubMed Abstract: 
  • Ricin A-chain (RTA) and saporin-L1 (SAP) catalyze adenosine depurination of 28S rRNA to inhibit protein synthesis and cause cell death. We present the crystal structures of RTA and SAP in complex with transition state analogue inhibitors. These tight-bin ...

    Ricin A-chain (RTA) and saporin-L1 (SAP) catalyze adenosine depurination of 28S rRNA to inhibit protein synthesis and cause cell death. We present the crystal structures of RTA and SAP in complex with transition state analogue inhibitors. These tight-binding inhibitors mimic the sarcin-ricin recognition loop of 28S rRNA and the dissociative ribocation transition state established for RTA catalysis. RTA and SAP share unique purine-binding geometry with quadruple pi-stacking interactions between adjacent adenine and guanine bases and 2 conserved tyrosines. An arginine at one end of the pi-stack provides cationic polarization and enhanced leaving group ability to the susceptible adenine. Common features of these ribosome-inactivating proteins include adenine leaving group activation, a remarkable lack of ribocation stabilization, and conserved glutamates as general bases for activation of the H(2)O nucleophile. Catalytic forces originate primarily from leaving group activation evident in both RTA and SAP in complex with transition state analogues.


    Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Vacuolar saporin AB259Saponaria officinalisMutation(s): 0 
EC: 3.2.2.22
Find proteins for Q2QEH4 (Saponaria officinalis)
Explore Q2QEH4 
Go to UniProtKB:  Q2QEH4
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
C2X
Query on C2X

Download Ideal Coordinates CCD File 
A, B
9,9'-{(2R,3R,3aR,5S,7aR,9R,10R,10aR,12S,23R,25aR,27R,28R,28aR,30S,32aR,35aR,37S,39aR)-9-(6-amino-9H-purin-9-yl)-34-[(4-amino-5H-pyrrolo[3,2-d]pyrimidin-7-yl)methyl]-5,12,23,30,37-pentahydroxy-3,10,28-trimethoxy-5,12,23,30,37-pentaoxidotetracosahydro-2H,7H,25H-trifuro[3,2-f:3',2'-l:3'',2''-x]pyrrolo[3,4-r][1,3,5,9,11,15,17,21,23,27,29,2,4,10,16,22,28]undecaoxazapentaphosphacyclopentatriacontine-2,27-diyl}bis(2-amino-3,9-dihydro-6H-purin-6-one)
C51 H72 N21 O29 P5
UYGVCRAKTIGHOS-DFLHJNKYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
C2XKi :  8.699999809265137   nM  PDBBind
C2XKi:  3.9000000953674316   nM  Binding MOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.184 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.555α = 78.87
b = 52.573β = 66.32
c = 54.369γ = 80.58
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
CBASSdata collection
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-12-08
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description