Characterisation of Mesorhizobium huakuii cyclic -glucan
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چکیده
Periplasmic and extracellular glucans of Mesorhizobium huakuii were isolated and characterized by compositional and MALDI-TOF analyses, as well as H and C NMR spectroscopy. It was shown that M. huakuii produces a cyclic -glucan composed entirely of nonbranched glucose chains and unmodified by nonsugar substituents. The degree of polymerisation of the cyclic oligosaccharides was estimated to be in the range from 17 to 28. The most abundant glucan molecules contained 22 glucose residues. Glucose residues within the glucan were connected by -(1,2) glycosidic linkages. The cyclic glucan produced by M. huakuii is quite similar to the periplasmic -(1,2) glucans synthesized by Agrobacterium and Sinorhizobium genera. The synthesis of -glucan in M. huakuii is osmoregulated and this glucan could function as an osmoprotectant in free living cells.
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