9NK9 | pdb_00009nk9

Nano-body peptide complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 
    0.214 (Depositor), 0.173 (DCC) 
  • R-Value Work: 
    0.172 (Depositor), 0.177 (DCC) 
  • R-Value Observed: 
    0.176 (Depositor) 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Evaluation of AlphaFold modeling for elucidation of nanobody-peptide epitope interactions.

Sachdev, S.Roy, S.Saha, S.J.Zhao, G.Kumariya, R.Creemer, B.A.Yin, R.Pierce, B.G.Bewley, C.A.Cheloha, R.W.

(2025) J Biological Chem 301: 110268-110268

  • DOI: https://doi.org/10.1016/j.jbc.2025.110268
  • Primary Citation of Related Structures:  
    9NK9

  • PubMed Abstract: 

    Models of Ab-antigen complexes can be used to understand interaction mechanisms and for improving affinity. This study evaluates the use of the protein structure prediction algorithm AlphaFold (AF) for exploration of interactions between peptide epitope tags and the smallest functional antibody fragments, nanobodies (Nbs). Although past studies of AF for modeling antibody-target (antigen) interactions suggested modest algorithm performance, those were primarily focused on Ab-protein interactions, while the performance and utility of AF for Nb-peptide interactions, which are generally less complex due to smaller antigens, smaller binding domains, and fewer chains, is less clear. In this study we evaluated the performance of AF for predicting the structures of Nbs bound to experimentally validated, linear, short peptide epitopes (Nb-tag pairs). We expanded the pool of experimental data available for comparison through crystallization and structural determination of a previously reported Nb-tag complex (Nb 127 ). Models of Nb-tag pair structures generated from AF were variable with respect to consistency with experimental data, with good performance in just over half (4 out of 6) of cases. Even among Nb-tag pairs successfully modeled in isolation, efforts to translate modeling to more complex contexts failed, suggesting an underappreciated role of the size and complexity of inputs in AF modeling success. Finally, the model of a Nb-tag pair with minimal previous characterization was used to guide the design of a peptide-electrophile conjugate that undergoes covalent crosslinking with Nb upon binding. These findings highlight the utility of minimized antibody and antigen structures to maximize insights from AF modeling.


  • Organizational Affiliation
    • Laboratory of Bioorganic Chemistry; National Institutes of Diabetes, Digestive, and Kidney Diseases; National Institutes of Health, USA.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nanobody132Lama glamaMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
SER-PHE-GLU-ASP-PHE-TRP-LYS-GLY-GLU-ASP10synthetic constructMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free:  0.214 (Depositor), 0.173 (DCC) 
  • R-Value Work:  0.172 (Depositor), 0.177 (DCC) 
  • R-Value Observed: 0.176 (Depositor) 
Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.876α = 90
b = 46.876β = 90
c = 91.184γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease (NIH/NIDDK)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2025-05-28
    Type: Initial release
  • Version 1.1: 2025-06-04
    Changes: Database references
  • Version 1.2: 2025-07-09
    Changes: Database references