8QTB | pdb_00008qtb

MUC5AC D'D3CysD1 domains. SNP rs36189285: Arg996Gln.

• PDB DOI: https://doi.org/10.2210/pdb8QTB/pdb
• EM Map EMD-18648: EMDB EMDataResource

• Classification: STRUCTURAL PROTEIN
• Organism(s): Homo sapiens
• Expression System: Cricetulus griseus
• Mutation(s): Yes 


• Deposited: 2023-10-12 Released: 2025-03-12 
• Deposition Author(s): Trillo-Muyo, S., Hansson, G.C.
• Funding Organization(s): European Research Council (ERC), National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID), Swedish Research Council, Knut and Alice Wallenberg Foundation

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 2.94 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Starting Model: in silico

Literature

Structure of the MUC5AC VWD3 assembly responsible for the formation of net-like mucin polymers.

Trillo-Muyo, S., Ermund, A., Hansson, G.C.

(2025) EMBO Rep 

• PubMed: 40016425 
• DOI: https://doi.org/10.1038/s44319-025-00395-8
• Primary Citation of Related Structures:  
  8QSP, 8QTB, 8QTV, 8R1U, 8R1Z


• PubMed Abstract: 
  

  Gel-forming mucins MUC5AC and MUC5B constitute the main structural component of the mucus in the respiratory system. Secreted mucins interact specifically with each other and other molecules giving mucus specific properties. We determined the cryoEM structures of the wild type D3 assembly of the human MUC5AC mucin and the structural single nucleotide polymorphisms (SNP) variants Arg996Gln and Arg1201Trp that affect intermolecular interactions. Our structures explain the MUC5AC N-terminal non-covalent oligomerization after secretion. The D3 assembly forms covalent dimers that can appear in two alternative conformations, open and closed, where the closed conformation dimers interact through an arginine-rich loop in the TIL3 domain to form tetramers. Our study provides a model to explain MUC5AC net-like structures and how the two SNPs will affect mucus organization, something that might affect lung and other diseases.

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Organizational Affiliation: 

Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530, Gothenburg, Sweden. [e-mail].

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by (software)

Biological Assembly Evidence: electron microscopy

Macromolecule Content

• Total Structure Weight: 156.51 kDa 
• Atom Count: 5,050 
• Modelled Residue Count: 662 
• Deposited Residue Count: 1,444 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Mucin-5AC	A, B	722	Homo sapiens	Mutation(s): 1  Gene Names: MUC5AC
UniProt & NIH Common Fund Data Resources
Find proteins for P98088 (Homo sapiens) Explore P98088  Go to UniProtKB:  P98088
PHAROS:  P98088 GTEx:  ENSG00000215182

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA (Subject of Investigation/LOI)	C [auth A], D [auth B]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 2.94 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
RECONSTRUCTION	cryoSPARC	4.2.1
MODEL REFINEMENT	PHENIX	1.20.1-4487

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-03-12 
Deposition Author(s): Trillo-Muyo, S., Hansson, G.C.

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Funding Organization	Location	Grant Number
European Research Council (ERC)	European Union	694181
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)	United States	U01AI095473
Swedish Research Council	Sweden	2017-00958
Knut and Alice Wallenberg Foundation	Sweden	2017-0028

Revision History  

• Version 1.0: 2025-03-12
  Type: Initial release