Fig. 8
From: Tuning heterologous glucan biosynthesis in yeast to understand and exploit plant starch diversity
Model of the relationship between the SS to BE ratio, glucan structure, and solubility. In strains A and B, where the SS/BE ratio is highest, a mixture of insoluble (ins) and soluble (sol) glucans is formed. These glucans are characterized by abundant long chains that frequently adopt double-helical secondary structures as in plant amylopectin, despite probably imperfect branching patterns. If the SS/BE ratio is decreased (strains C and D), chains become shorter and secondary structures less likely, resulting in exclusively soluble glucans. In strains E and F, where elongating SS activity is limited, glucans have a large portion of short glucan chains that directly derive from BE activity and have not (or only little) been elongated by a SS. These glucans have a wavelength of maximum absorption after iodine complexion (λmax) similar to glycogen, indicative of few to no secondary structures