Comments: |
This enzyme is the cyclization domain of cyclic β-1,2-glucan synthase. Enzymes from Brucella abortus and Thermoanaerobacter italicus were characterized. The cyclization domain of cyclic β-1,2-glucan synthase is flanked by an N-terminal β-1,2-glucosyltransferase domain (a UDP-α-D-glucose-dependent synthase, not EC 2.4.1.391) and a C-terminal β-1,2-glucoside phosphorylase domain (cf. EC 2.4.1.333), with the former responsible for elongation and the latter for chain length control. The cyclization domain of Thermoanaerobacter italicus cyclizes linear oligosaccharides with a degree of polymerization (DP) of 21 or higher to produce cyclic glucans with DP 17 or higher. The cyclization domain also disproportionates linear β-1,2-glucooligosaccharides without cycling. The entire cyclic β-1,2-glucan synthase from Brucella abortus synthesizes cyclic β-1,2-glucans with DP 17-22. |
References: |
1. |
Inon de Iannino, N., Briones, G., Tolmasky, M. and Ugalde, R.A. Molecular cloning and characterization of cgs, the Brucella abortus cyclic β(1-2) glucan synthetase gene: genetic complementation of Rhizobium meliloti ndvB and Agrobacterium tumefaciens chvB mutants. J. Bacteriol. 180 (1998) 4392–4400. [DOI] [PMID: 9721274] |
2. |
Guidolin, L.S., Ciocchini, A.E., Inon de Iannino, N. and Ugalde, R.A. Functional mapping of Brucella abortus cyclic β-1,2-glucan synthase: identification of the protein domain required for cyclization. J. Bacteriol. 191 (2009) 1230–1238. [DOI] [PMID: 19074375] |
3. |
Guidolin, L.S., Morrone Seijo, S.M., Guaimas, F.F., Comerci, D.J. and Ciocchini, A.E. Interaction network and localization of Brucella abortus membrane proteins involved in the synthesis, transport, and succinylation of cyclic β-1,2-glucans. J. Bacteriol. 197 (2015) 1640–1648. [DOI] [PMID: 25733613] |
4. |
Tanaka, N., Saito, R., Kobayashi, K., Nakai, H., Kamo, S., Kuramochi, K., Taguchi, H., Nakajima, M. and Masaike, T. Functional and structural analysis of a cyclization domain in a cyclic β-1,2-glucan synthase. Appl. Microbiol. Biotechnol. 108:187 (2024). [DOI] [PMID: 38300345] |
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