9F6H | pdb_00009f6h

Crystal structure of bovine alpha-chymotrypsin in complex with the bicyclic peptide inhibitor MP5.4.3


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.42 Å
  • R-Value Free: 
    0.286 (Depositor), 0.285 (DCC) 
  • R-Value Work: 
    0.212 (Depositor), 0.212 (DCC) 
  • R-Value Observed: 
    0.215 (Depositor) 

Starting Model: experimental
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Literature

Screening macrocyclic peptide libraries by yeast display allows control of selection process and affinity ranking.

Linciano, S.Mazzocato, Y.Romanyuk, Z.Vascon, F.Farrera-Soler, L.Will, E.Xing, Y.Chen, S.Kumada, Y.Simeoni, M.Scarso, A.Cendron, L.Heinis, C.Angelini, A.

(2025) Nat Commun 16: 5367-5367

  • DOI: https://doi.org/10.1038/s41467-025-60907-x
  • Primary Citation of Related Structures:  
    9F6H

  • PubMed Abstract: 

    Macrocyclic peptides represent an attractive drug modality due to their favourable properties and amenability to in vitro evolution techniques such as phage or mRNA display. Although very powerful, these technologies are not without limitations. In this work, we address some of their drawbacks by developing a yeast display-based strategy to generate, screen and characterise structurally diverse disulfide-cyclised peptides. The use of quantitative flow cytometry enables real-time monitoring of the screening of millions of individual macrocyclic peptides, leading to the identification of ligands with good binding properties to five different protein targets. X-ray analysis of a selected ligand in complex with its target reveals optimal shape complementarity and extensive surface interaction, explaining its exquisite affinity and selectivity. The yeast display-based approach described here offers a facile, quantitative and cost-effective alternative to rapidly and efficiently discover and characterise genetically encoded macrocyclic peptide ligands with sufficiently good binding properties against therapeutically relevant targets.


  • Organizational Affiliation
    • Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172, Venice, Italy.

Macromolecules

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chymotrypsin A chain A13Bos taurusMutation(s): 0 
EC: 3.4.21.1
UniProt
Find proteins for P00766 (Bos taurus)
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Go to UniProtKB:  P00766
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00766
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Chymotrypsin A chain B131Bos taurusMutation(s): 0 
EC: 3.4.21.1
UniProt
Find proteins for P00766 (Bos taurus)
Explore P00766 
Go to UniProtKB:  P00766
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00766
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Chymotrypsin A chain C97Bos taurusMutation(s): 0 
EC: 3.4.21.1
UniProt
Find proteins for P00766 (Bos taurus)
Explore P00766 
Go to UniProtKB:  P00766
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00766
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  • Reference Sequence

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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
Bicyclic peptide MP5.4.3D [auth L]14synthetic constructMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.42 Å
  • R-Value Free:  0.286 (Depositor), 0.285 (DCC) 
  • R-Value Work:  0.212 (Depositor), 0.212 (DCC) 
  • R-Value Observed: 0.215 (Depositor) 
Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 103.471α = 90
b = 103.471β = 90
c = 46.421γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling
MOLREPphasing
REFMACrefinement
PDB-REDOrefinement
Cootmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Italian Ministry of EducationItaly--

Revision History  (Full details and data files)

  • Version 1.0: 2025-05-28
    Type: Initial release
  • Version 1.1: 2025-07-09
    Changes: Database references