The polysaccharide β-1,2-glucan consists of repeating units of glucose linked together by β-1,2-glycosidic bonds. Cyclic β-1,2-glucans (CβGs) occur in different bacterial species and have a role in bacterial infections and symbiotic relationships. CβG biosynthesis is catalyzed by cyclic β-1,2-glucan synthase (CGS), an enzyme that catalyzes the cyclization (closed ring formation) of linear β-1,2-glucan (LβG).