3S70

Crystal structure of active caspase-6 bound with Ac-VEID-CHO solved by As-SAD


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.63 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.165 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Get phases from arsenic anomalous scattering: de novo SAD phasing of two protein structures crystallized in cacodylate buffer

Liu, X.Zhang, H.Wang, X.-J.Li, L.-F.Su, X.-D.

(2011) PLoS One 6: e24227-e24227

  • DOI: 10.1371/journal.pone.0024227
  • Primary Citation of Related Structures:  
    3S2S, 3S70

  • PubMed Abstract: 
  • The crystal structures of two proteins, a putative pyrazinamidase/nicotinamidase from the dental pathogen Streptococcus mutans (SmPncA) and the human caspase-6 (Casp6), were solved by de novo arsenic single-wavelength anomalous diffraction (As-SAD) phasing method ...

    The crystal structures of two proteins, a putative pyrazinamidase/nicotinamidase from the dental pathogen Streptococcus mutans (SmPncA) and the human caspase-6 (Casp6), were solved by de novo arsenic single-wavelength anomalous diffraction (As-SAD) phasing method. Arsenic (As), an uncommonly used element in SAD phasing, was covalently introduced into proteins by cacodylic acid, the buffering agent in the crystallization reservoirs. In SmPncA, the only cysteine was bound to dimethylarsinoyl, which is a pentavalent arsenic group (As (V)). This arsenic atom and a protein-bound zinc atom both generated anomalous signals. The predominant contribution, however, was from the As anomalous signals, which were sufficient to phase the SmPncA structure alone. In Casp6, four cysteines were found to bind cacodyl, a trivalent arsenic group (As (III)), in the presence of the reducing agent, dithiothreitol (DTT), and arsenic atoms were the only anomalous scatterers for SAD phasing. Analyses and discussion of these two As-SAD phasing examples and comparison of As with other traditional heavy atoms that generate anomalous signals, together with a few arsenic-based de novo phasing cases reported previously strongly suggest that As is an ideal anomalous scatterer for SAD phasing in protein crystallography.


    Organizational Affiliation

    State Key Laboratory of Protein and Plant Gene Research and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Caspase-6 AC278Homo sapiensMutation(s): 0 
Gene Names: CASP6MCH2
EC: 3.4.22.59
Find proteins for P55212 (Homo sapiens)
Explore P55212 
Go to UniProtKB:  P55212
NIH Common Fund Data Resources
PHAROS:  P55212
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
aldehyde inhibitor Ac-VEID-CHO BD5N/AMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.63 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.165 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.39α = 90
b = 89.45β = 111.7
c = 61.13γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASESphasing
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-04-11
    Type: Initial release
  • Version 1.1: 2012-12-12
    Changes: Other