Molecular-level architecture of Chlamydomonas reinhardtii’s glycoprotein-rich cell wall
Alexandre Poulhazan, Alexandre A. Arnold, Frédéric Mentink‐Vigier, Artur Muszyński, Parastoo Azadi, Adnan Halim, Sergey Y. Vakhrushev, Hiren J. Joshi, Tuo Wang, Dror E. Warschawski, Isabelle Marcotte
Abstract
Microalgae are a renewable and promising biomass for large-scale biofuel, food and nutrient production. However, their efficient exploitation depends on our knowledge of the cell wall composition and organization as it can limit access to high-value molecules. Here we provide an atomic-level model of the non-crystalline and water-insoluble glycoprotein-rich cell wall of Chlamydomonas reinhardtii. Using in situ solid-state and sensitivity-enhanced nuclear magnetic resonance, we reveal unprecedented details on the protein and carbohydrate composition and their nanoscale heterogeneity, as well as the presence of spatially segregated protein- and glycan-rich regions with different dynamics and hydration levels. We show that mannose-rich lower-molecular-weight proteins likely contribute to the cell wall cohesion by binding to high-molecular weight protein components, and that water provides plasticity to the cell-wall architecture. The structural insight exemplifies strategies used by nature to form cell walls devoid of cellulose or other glycan polymers.