Properties and current applications of bacterial cyclic β-glucans and their derivatives

Abstract

Cyclic b-glucans are unique constituents that are found in the periplasmic space and extracellular media of Agrobacterium, Rhizobium, Bradyrhizobium, Rhodobacter, Xanthomonas, and Ralstonia species. Based on their glycosidic linkages, they are classified into three groups composed of cyclic b-(1,2), b-(1,3)-b-(1,6), and b-(1,2)-a-(1,6) linked glucans. Their degrees of polymerization vary ranging from 10 to 40 glucose residues, and the backbone structure can be modified with non-sugar moieties. Since the macrocyclic oligosaccharides possess their own characteristics such as inherent three-dimensional structures, hydrogen bonding, and complex-forming abilities, various possible applications would be of interest in the field of green chemistry, separation science, pharmaceutical, and food industries. In this review, we have addressed the properties and current applications of bio-sourced cyclic bglucans and their derivatives.

Cyclic β-glucans at the bacteria-host cells interphase: One sugar ring to rule them all

“…In the case of Bradyrhizobium, it has been proposed that their OPGs could sequester hydrophobic substances important for plant signalling such as flavonoids. This is a plausible hypothesis since the excellent capacity of the CβG to complex and solubilise flavonoids has been demonstrated (Cho et al, 2016;Park, 2016).…”

“…This is a plausible hypothesis since the excellent capacity of the CβG to complex and solubilise flavonoids has been demonstrated (Cho et al, 2016;Park, 2016). In the case of Bradyrhizobium, it has been proposed that their OPGs could sequester hydrophobic substances important for plant signalling such as flavonoids.…”

“…Different studies indicate that CβG and derivatives can be utilised as complexing agents to enhance solubility of guest molecules (Park, 2016). Their ability as chiral selectors for various enantiomers, as catalytic carbohydrates for methanolysis, and as morphology-directing agents for the synthesis of selenium nanowires has also been described (Cho, Jeong, Choi, & Jung, 2016;Jeong, Kim, Dindulkar, Lee, & Jung, 2015;Lee, Cho, & Jung, 2009). Macrocyclic compounds are very interesting in supramolecular chemistry as their conformation results in high affinity and/or selectivity for specific interactions, useful in the design of artificial host in host-guest chemistry (Cho et al, 2016).…”

Glycosyl Dioxalenium Ions as Reactive Intermediates of Automated Electrochemical Assembly

“…We have been interested in synthesis of cyclic β‐(1,3)‐β‐(1,6)‐glucan [3] as a target oligosaccharide of automated electrochemical assembly (Figure 2). [4] Cyclic β‐glucans including the cyclic β‐(1,3)‐β‐(1,6)‐glucan have potential applications for separation of chiral molecules, drug delivery, and catalyst [3c] . Although synthesis of hexasaccharide, which is a half structure of the cyclic oligosaccharide, has already been achieved, the yield was not high enough to complete the total synthesis [5] .…”

Modeled 3D-Structures of Proteobacterial Transglycosylases from Glycoside Hydrolase Family 17 Give Insight in Ligand Interactions Explaining Differences in Transglycosylation Products

“…Bacterial transglycosylases are involved in various functions. Periplasmic synthesis of β-glucans and cyclic β-glucans has been reported in some species [9] that may have roles in protection against antibiotics [10], plant-microbe interaction, or osmoregulation [11]. The enzymes identified to be involved in this synthesis are modular membrane-anchored proteins (NdvB), including GH17 catalytic modules.…”