9GOS | pdb_00009gos

CryoEM structure of the native Chlamydomonas reinhardtii Flagella Membrane Glycoprotein 1B.

• PDB DOI: https://doi.org/10.2210/pdb9GOS/pdb
• EM Map EMD-51499: EMDB EMDataResource

• Classification: MEMBRANE PROTEIN
• Organism(s): Chlamydomonas reinhardtii
• Mutation(s): No 


• Deposited: 2024-09-06 Released: 2025-05-07 
• Deposition Author(s): Nievergelt, A.P., Hoepfner, L.M., Matrino, F., Scholz, M., Foster, H.E., Rodenfels, J., von Appen, A., Hippler, M., Pigino, G.
• Funding Organization(s): Human Frontier Science Program (HFSP), European Molecular Biology Organization (EMBO), European Research Council (ERC), German Research Foundation (DFG)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.10 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Unwrapping the Ciliary Coat: High-Resolution Structure and Function of the Ciliary Glycocalyx.

Hoepfner, L.M., Nievergelt, A.P., Matrino, F., Scholz, M., Foster, H.E., Rodenfels, J., von Appen, A., Hippler, M., Pigino, G.

(2025) Adv Sci (Weinh) 12: e2413355-e2413355

• PubMed: 40041987 
• DOI: https://doi.org/10.1002/advs.202413355
• Primary Citation Related Structures: 
  9GOS


• PubMed Abstract: 
  

  The glycocalyx, a highly heterogeneous glycoprotein layer of cilia regulates adhesion and force transduction and is involved in signaling. The high-resolution molecular architecture of this layer is currently not understood. The structure of the ciliary coat is described in the green alga Chlamydomonas reinhardtii by cryo-electron tomography and proteomic approaches and the high-resolution cryoEM structure of the main component, FMG1B is solved. FMG1B is described as a mucin orthologue which lacks the major O-glycosylation of mammalian mucins but is N-glycosylated. FMG1A, a previously undescribed isoform of FMG1B is expressed in C. reinhardtii. By microflow-based adhesion assays, increased surface adhesion in the glycocalyx deficient double-mutant fmg1b-fmg1a is observed. It is found this mutant is capable of surface-gliding, with neither isoform required for extracellular force transduction by intraflagellar transport. The results find FMG1 to form a protective layer with adhesion-regulative instead of adhesion-conferring properties and an example of an undescribed class of mucins.

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Organizational Affiliation: 
• Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143, Münster, Germany.
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany.
Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany.
Human Technopole, V.le Rita Levi-Montalcini, 1, Milan, 20017, Italy.
Cluster of Excellence Physics of Life, TU Dresden, 01062, Dresden, Germany.
Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

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

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 448.23 kDa 
• Atom Count: 26,845 
• Modeled Residue Count: 3,878 
• Deposited Residue Count: 4,545 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Flagella Membrane Glycoprotein 1B	A	4,545	Chlamydomonas reinhardtii	Mutation(s): 0

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.10 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX	1.21.2_5419

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2025-05-07 
Deposition Author(s): Nievergelt, A.P., Hoepfner, L.M., Matrino, F., Scholz, M., Foster, H.E., Rodenfels, J., von Appen, A., Hippler, M., Pigino, G.

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Funding Organization	Location	Grant Number
Human Frontier Science Program (HFSP)	France	LT000515/2019
European Molecular Biology Organization (EMBO)	European Union	ALTF 891-2018
European Research Council (ERC)	European Union	819826
German Research Foundation (DFG)	Germany	HI 739/12-4

Revision History  

• Version 1.0: 2025-05-07
  Type: Initial release
  
• Version 1.1: 2025-11-19
  Changes: Data collection, Database references