We investigated the crystal structure and molecular arrangement of the linear (1 → 3)-α-d-glucan synthesized by glucosyltransferase GtfJ cloned from Streptococcus salivarius using sucrose as a substrate. The synthetic products had two morphologies: wavy fibril-like crystals as major and thin lamellae as minor products. Their structures were analyzed using electron microdiffraction, synchrotron X-ray powder diffraction, and solid-state ¹³C NMR spectroscopy. The fibrils and lamellae had the same allomorphic form but different molecular arrangements. The wet crystals were in a hydrated form, which converted into an anhydrous form with a significant decrease in crystallinity on drying. The hydrated and anhydrous forms had an extended-chain conformation with 2/1 helix, and the hydrated form was estimated to contain one water molecule per glucose residue. The long glucan chains were folded in the fibril crystals, while the short, extended chains were arranged perpendicular to the base plane of the lamellae.

中文翻译：

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体外合成的结晶线性（1→3）-α- d-葡聚糖的表征

我们研究了以蔗糖为底物从唾液链球菌中克隆的葡糖基转移酶GtfJ合成的线性（1→3）-α- d-葡聚糖的晶体结构和分子排列。合成产品具有两种形态：波浪状的原纤维状晶体为主要产物，薄的薄片为次要产物。使用电子微衍射，同步加速器X射线粉末衍射和固态¹³分析了它们的结构13 C NMR光谱。原纤维和薄片具有相同的同素异形形式，但分子排列不同。湿晶体为水合形式，其转化为无水形式，干燥时结晶度显着降低。水合形式和无水形式具有2/1螺旋的延伸链构象，并且据估计水合形式每个葡萄糖残基包含一个水分子。较长的葡聚糖链折叠在原纤维晶体中，而较短的延伸链则垂直于薄片的底面排列。