Functional Identification of the Dextransucrase Gene of Leuconostoc mesenteroides DRP105

Abstract

Leuconostoc mesenteroides DRP105 isolated from Chinese sauerkraut juice is an intensive producer of dextran. We report the complete genome sequence of Leu. mesenteroides DRP105. This strain contains a dextransucrase gene (dsr) involved in the production of dextran, possibly composed of glucose monomers. To explore the dextran synthesis mechanism of Leu. mesenteroides DRP105, we constructed a dsr-deficient strain derived from Leu. mesenteroides DRP105 using the Cre-loxP recombination system. The secondary structure prediction results showed that Leu. mesenteroides DRP105 dextransucrase (Dsr) was coded by dsr and contained 17.07% α-helices, 29.55% β-sheets, 10.18% β-turns, and 43.20% random coils. We also analyzed the dextran yield, monosaccharide change, organic acid, and amino-acid content of Leu. mesenteroides DRP105 and Leu. mesenteroides DRP105−Δdsr. The result showed that the lack of dsr changed the Leu. mesenteroides DRP105 sugar metabolism pathway, which in turn affected the production of metabolites.

In Silico Analysis of the Dextransucrase Obtained From Leuconostoc mesenteroides Strain IBUN 91.2.98

“…DSR-IBUN secondary structure prediction showed 39.03% random coils, 28.55% β-sheets, 20.89% α-helices, and 11.53% β-turns, which is comparable with what was obtained by Du et al 64 for L mesenteroides DRP105 dextransucrase.…”

“…In the alignment (Figure 1), it can be observed that DSR-IBUN is part of the GS subfamily, which indicates that the synthesized dextran has mainly α1,6 bonds, accompanied by α1,3 bonds. 60 DSR-IBUN secondary structure prediction showed 39.03% random coils, 28.55% β-sheets, 20.89% α-helices, and 11.53% β-turns, which is comparable with what was obtained by Du et al 64 for L mesenteroides DRP105 dextransucrase.…”