Crystal Structure of beta secetase in complex with 2-amino-3,6-dimethyl-6-(2-phenylethyl)-3,4,5,6-tetrahydropyrimidin-4-one

Experimental Data Snapshot

  • Resolution: 2.25 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 

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Conformational restriction approach to beta-secretase (BACE1) inhibitors III: Effective investigation of the binding mode by combinational use of X-ray analysis, isothermal titration calorimetry and theoretical calculations

Yonezawa, S.Fujiwara, K.Yamamoto, T.Hattori, K.Yamakawa, H.Muto, C.Hosono, M.Tanaka, Y.Nakano, T.Takemoto, H.Arisawa, M.Shuto, S.

(2013) Bioorg Med Chem 21: 6506-6522

  • DOI: https://doi.org/10.1016/j.bmc.2013.08.036
  • Primary Citation of Related Structures:  
    3WB4, 3WB5

  • PubMed Abstract: 

    For further investigation of BACE1 inhibitors using conformational restriction with sp(3) hybridized carbon, we applied this approach to 6-substituted aminopyrimidone derivatives 3 to improve the inhibitory activity by reducing the entropic energy loss upon binding to BACE1. Among eight stereoisomers synthesized, [trans-(1'R,2'R),6S] isomer 6 exhibited the best BACE1 inhibitory activity, which was statistically superior to that of the corresponding ethylene linker compound (R)-3. Combinational examinations of the binding mode of 6 were performed, which included isothermal titration calorimetry (ITC), X-ray crystallographic structure analysis and theoretical calculations, to clarify the effect of our conformational restriction approach. From the ITC measurement, the binding entropy of 6 was found to be ∼0.5kcal larger than that of (R)-3, which is considered to be affected by conformational restriction with a cyclopropane ring.

  • Organizational Affiliation

    Shionogi Innovation Center for Drug Discovery, Shionogi & Co., Ltd, Kita-21 Nishi-11 Kita-ku, Sapporo 001-0021, Japan; Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan. Electronic address: shuji.yonezawa@shionogi.co.jp.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-secretase 1416Homo sapiensMutation(s): 0 
Gene Names: BACE1BACEKIAA1149
UniProt & NIH Common Fund Data Resources
Find proteins for P56817 (Homo sapiens)
Explore P56817 
Go to UniProtKB:  P56817
GTEx:  ENSG00000186318 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP56817
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
0B3 PDBBind:  3WB4 Kd: 3.66e+4 (nM) from 1 assay(s)
BindingDB:  3WB4 IC50: 3.40e+4 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.25 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 102.208α = 90
b = 102.208β = 90
c = 169.984γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
CrystalCleardata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-10-02
    Type: Initial release
  • Version 1.1: 2013-10-23
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Refinement description