9B4H

Chlamydomonas reinhardtii mastigoneme filament

This is a non-PDB format compatible entry.

Summary for 9B4H

• Entry DOI: 10.2210/pdb9b4h/pdb
• EMDB information: 43889 43890 43891 43892
• Descriptor: Tyrosine-protein kinase ephrin type A/B receptor-like domain-containing protein, alpha-D-galactopyranose, C-type lectin domain-containing protein, ... (10 entities in total)
• Functional Keywords: mastigoneme, glycosylated hydroxyproline, structural protein
• Biological source: Chlamydomonas reinhardtii; More
• Total number of polymer chains: 3
• Total formula weight: 1340327.84

Authors

Dai, J.,Ma, M.,Zhang, R.,Brown, A. (deposition date: 2024-03-20, release date: 2024-04-10)

Primary citation

Dai, J.,Ma, M.,Niu, Q.,Eisert, R.J.,Wang, X.,Das, P.,Lechtreck, K.F.,Dutcher, S.K.,Zhang, R.,Brown, A.
Mastigoneme structure reveals insights into the O-linked glycosylation code of native hydroxyproline-rich helices.
Cell, 2024

PubMed Abstract: Hydroxyproline-rich glycoproteins (HRGPs) are a ubiquitous class of protein in the extracellular matrices and cell walls of plants and algae, yet little is known of their native structures or interactions. Here, we used electron cryomicroscopy (cryo-EM) to determine the structure of the hydroxyproline-rich mastigoneme, an extracellular filament isolated from the cilia of the alga Chlamydomonas reinhardtii. The structure demonstrates that mastigonemes are formed from two HRGPs (a filament of MST1 wrapped around a single copy of MST3) that both have hyperglycosylated poly(hydroxyproline) helices. Within the helices, O-linked glycosylation of the hydroxyproline residues and O-galactosylation of interspersed serine residues create a carbohydrate casing. Analysis of the associated glycans reveals how the pattern of hydroxyproline repetition determines the type and extent of glycosylation. MST3 possesses a PKD2-like transmembrane domain that forms a heteromeric polycystin-like cation channel with PKD2 and SIP, explaining how mastigonemes are tethered to ciliary membranes.

PubMed: 38552624
DOI: 10.1016/j.cell.2024.03.005

Experimental method

ELECTRON MICROSCOPY (3.1 Å)