Correlation between crystalline cellulose structure and cellulose synthase complex shape: a spectroscopic study with unicellular freshwater alga Micrasterias

Cellulose is synthesized into fibrils by enzyme complexes called cellulose synthase complexes (CSCs). We analyzed cellulose fibrils produced in a dividing unicellular freshwater alga Micrasterias with vibrational sum frequency generation (SFG) spectroscopy. It is known that cellulose in the daughter semi-cell of Micrasterias is synthesized by the isolated individual rosette-shape CSC, while cellulose in the mother semi-cell is produced by hexagonal arrays of rosette-shape CSCs. Comparing the SFG spectra of cellulose in these two regions of a single cell of Micrasterias showed intriguing correlations between the polymorphic structure and crystal size of cellulose and the shape and size of the CSCs. This information may provide a foundation needed to understand what determines the cellulose structure and crystallinity in plant cell walls.