From Prokaryotes to Eukaryotes: Insights Into the Molecular Structure of Glycogen Particles

Abstract

Glycogen is a highly-branched polysaccharide that is widely distributed across the three life domains. It has versatile functions in physiological activities such as energy reserve, osmotic regulation, blood glucose homeostasis, and pH maintenance. Recent research also confirms that glycogen plays important roles in longevity and cognition. Intrinsically, glycogen function is determined by its structure that has been intensively studied for many years. The recent association of glycogen α-particle fragility with diabetic conditions further strengthens the importance of glycogen structure in its function. By using improved glycogen extraction procedures and a series of advanced analytical techniques, the fine molecular structure of glycogen particles in human beings and several model organisms such as Escherichia coli, Caenorhabditis elegans, Mus musculus, and Rat rattus have been characterized. However, there are still many unknowns about the assembly mechanisms of glycogen particles, the dynamic changes of glycogen structures, and the composition of glycogen associated proteins (glycogen proteome). In this review, we explored the recent progresses in glycogen studies with a focus on the structure of glycogen particles, which may not only provide insights into glycogen functions, but also facilitate the discovery of novel drug targets for the treatment of diabetes mellitus.

Glycogen phase separation drives macromolecular rearrangement and asymmetric division inE. coli

“…In the bacteriology literature, glycogen accumulations are often described as “granules” or “inclusion bodies” due to their round or oval shapes when visualized by electron microscopy (Shively, 1974; Preiss, 1984; Liu et al , 2021b; Alonso-Casajús et al , 2006; Preiss & Romeo, 1994). These terms can give the impression of a solid.…”

Glycogen Metabolism in Candida albicans Impacts Fitness and Virulence during Vulvovaginal and Invasive Candidiasis

“…In vitro enzymatic or glucose isotope labeling approaches will be required to conclusively validate these hypotheses. It should also be pointed out that glycogen from different species displays heterogeneous glycogen particles with respect to size, polymerization, and branching ( 51 – 53 ), as demonstrated by in vitro enzymatic assembly assays that used branching enzymes from different species ( 54 , 55 ). Such disparities in structure also alter the degradation kinetics.…”

Comparative analysis between two GT4 glycosyltransferases related to polysaccharide biosynthesis inRhodococcus jostiiRHA1

“…It was described that glycogen from oyster possesses a heterogeneous structure given the presence of glucan chains with different lengths, where seven glucose moieties are considered the average size [58,59]. In contrast, glycogen from bacteria and eukaryotes is composed of identical branches with 12-14 glucose units [60][61][62].…”