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Novel Dextransucrase Gtf-DSM, Highly Similar in Sequence to Reuteransucrase GtfO, Displays Unique Product Specificity
journal contribution
posted on 2019-11-08, 14:46 authored by Ziwei Chen, Yuqing Tian, Wenli Zhang, Cuie Guang, Xiangfeng Meng, Wanmeng MuLactic
acid bacteria are known to produce extracellular polysaccharides
such as α-glucan, levan, and inulin, which are promising for
applications in food systems because of their prebiotic properties.
In this work, a novel glucansucrase (GS) Gtf-DSM from Lactobacillus ingluviei DSM 14792 was recombinantly
expressed and biochemically characterized as a dextransucrase capable
of producing a dextran polysaccharide with four types of linkages,
including 69% (α1 → 6), 24% (α1 → 3), 6%
(α1 → 4), and 1% (α1 → 2). Intriguingly,
the dextransucrase Gtf-DSM had a sequence identity of 99.3% with the
reuteransucrase GtfO producing a reuteran with 21% (α1 →
6) and 79% (α1 → 4) linkages. Thus, the dextransucrase
Gtf-DSM is a unique target for understanding the linkage specificity
of GSs and the investigation of site-directed mutagenesis using Gtf-DSM
and GtfO as templates is underway.