9N5Z | pdb_00009n5z

Hemagglutinin CA09 homotrimer bound to AMB38310/AMB38599 Fab


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.20 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Starting Models: in silico, experimental
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wwPDB Validation   3D Report Full Report


This is version 1.0 of the entry. See complete history


Literature

Predicting the conformational flexibility of antibody and T cell receptor complementarity-determining regions.

Spoendlin, F.C.Fernandez-Quintero, M.L.Raghavan, S.S.R.Turner, H.L.Gharpure, A.Loeffler, J.R.Wong, W.K.Bujotzek, A.Georges, G.Ward, A.B.Deane, C.M.

(2025) Nat Mach Intell 7: 1755-1767

  • DOI: https://doi.org/10.1038/s42256-025-01131-6
  • Primary Citation of Related Structures:  
    9N5Y, 9N5Z

  • PubMed Abstract: 

    Many proteins are highly flexible and their ability to adapt their shape can be fundamental to their functional properties. For example, the flexibility of antibody complementarity-determining region (CDR) loops influences binding affinity and specificity, making it a key factor in understanding and designing antigen interactions. With methods such as AlphaFold, it is possible to computationally predict a single, static protein structure with high accuracy. However, the reliable prediction of structural flexibility has not yet been achieved. A major factor limiting such predictions is the scarcity of suitable training data. Here we focus on predicting the structural flexibility of functionally important antibody and T cell receptor CDR3 loops. To this end, we constructed ALL-conformations by extracting CDR3s and CDR3-like loop motifs from all structures deposited in the Protein Data Bank. This dataset comprises 1.2 million loop structures representing more than 100,000 unique sequences and captures all experimentally observed conformations of these motifs. Using this dataset, we develop ITsFlexible, a deep learning tool with graph neural network architecture. We trained the model to binary classify CDR loops as 'rigid' or 'flexible' from inputs of antibody structures. ITsFlexible outperforms all alternative approaches on our crystal structure datasets and successfully generalizes to molecular dynamics simulations. We also used ITsFlexible to predict the flexibility of three CDRH3 loops with no solved structures and experimentally determined their conformations using cryogenic electron microscopy.


  • Organizational Affiliation
    • Department of Statistics, University of Oxford, Oxford, UK.

Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
heavy chain antibody Fab AMB38599126Homo sapiensMutation(s): 0 
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Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
light chain antibody Fab AMB38310108Homo sapiensMutation(s): 0 
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Hemagglutinin
C, D, E
326Influenza A virus (A/California/01/2009(H1N1))Mutation(s): 0 
Gene Names: HA
UniProt
Find proteins for A0A3S5H8L7 (Influenza A virus)
Explore A0A3S5H8L7 
Go to UniProtKB:  A0A3S5H8L7
Entity Groups  
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UniProt GroupA0A3S5H8L7
Glycosylation
Glycosylation Sites: 5
Sequence Annotations
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  • Reference Sequence
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
Hemagglutinin
F, G, H
171Influenza A virus (A/California/01/2009(H1N1))Mutation(s): 0 
Gene Names: HA
UniProt
Find proteins for G0KSL8 (Influenza A virus)
Explore G0KSL8 
Go to UniProtKB:  G0KSL8
Entity Groups  
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UniProt GroupG0KSL8
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download Ideal Coordinates CCD File 
I [auth C]
J [auth C]
K [auth C]
L [auth C]
M [auth C]
I [auth C],
J [auth C],
K [auth C],
L [auth C],
M [auth C],
N [auth D],
O [auth D],
P [auth D],
Q [auth D],
R [auth D],
S [auth E],
T [auth E],
U [auth E],
V [auth E],
W [auth E]
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.20 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.21.2_5419
RECONSTRUCTIONcryoSPARCv4.5

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2025-11-12
    Type: Initial release