Functional role and folding properties of the glucan-binding domain of oral bacterial glucansucrase

Streptococcus sobrinus glucansucrase transfers glucose from sucrose to dextran and synthesizes water-insoluble glucan by creating α-1,3-branches along the dextran polysaccharide. Glucansucrase contains a catalytic domain and a glucan-binding domain (GBd) with six tandem repeats. We here examined the role of GBd in the glucansucrase, focusing on its impact on enzymatic activity, dextran binding, and structural stability. By generating seven deletion mutants and a circularly permuted protein, our research demonstrates that at least four GBd repeats and proper domain orientation are required for efficient glucosyl transfer. Moreover, circular dichroism and thermal unfolding analyses revealed that glucosyl transfer efficiency is linked to cooperative interdomain folding rather than dextran-binding affinity. These findings highlight the importance of interdomain allostery in optimizing glucansucrase function., , # Data from: Functional role and folding properties of the glucan-binding domain of oral bacterial glucansucrase

Dataset DOI: [10.5061/dryad.bcc2fqzr5](10.5061/dryad.bcc2fqzr5)

## Description of the data and file structure

Comments and requests should be addressed to Hideyuki Komatsu: [[e-mail]](mailto:[e-mail]).

### Files and variables

#### File: Figure1_GTF-I_homology_model_data.py

**Description:** Homology modeling data of glucosyltransferase (GTF)-I based on the *Lactobacillus* GTF-180 crystal structure. The file can be visualized by UCSF ChimeraX ([https://www.cgl.ucsf.edu/chimerax/](https://www.cgl.ucsf.edu/chimerax/)).

#### File: Figure3_GS_activity.csv

**Description:** Glucosyl transfer activities plotted against dextran concentration.

##### Variables

* Dextran1: dextran concentration in μg/mL for GSdGBd3R, GSdGBd4RS, GSdGBd4RL, GSdGBd5R, and DCP.
* GSdGBd3R: glucosyl transfer activities for GSdGBd3R.
* GSdGBd4RS: glucosyl transfer act...,

变形链球菌（Streptococcus sobrinus）所分泌的葡聚糖蔗糖酶（glucansucrase）可将蔗糖中的葡萄糖转移至葡聚糖底物，并通过在葡聚糖多糖链上引入α-1,3分支来合成水不溶性葡聚糖。该酶包含一个催化结构域与一个带有六个串联重复序列的葡聚糖结合结构域（glucan-binding domain, GBd）。本研究针对葡聚糖蔗糖酶中的葡聚糖结合结构域的功能展开探究，重点考察其对酶促活性、葡聚糖结合能力以及结构稳定性的影响。研究团队通过构建7种缺失突变体与1种环状置换蛋白，证实至少需要4个葡聚糖结合结构域重复序列以及正确的结构域取向，方可实现高效的糖基转移反应。此外，圆二色谱与热变性分析结果显示，糖基转移效率与结构域间的协同折叠密切相关，而非仅取决于葡聚糖结合亲和力。上述研究结果凸显了结构域间别构效应在优化葡聚糖蔗糖酶功能中的关键作用。
# 数据来源：口腔细菌葡聚糖蔗糖酶葡聚糖结合结构域的功能角色与折叠特性
数据集DOI：10.5061/dryad.bcc2fqzr5

## 数据与文件结构说明
如有疑问或请求，请联系Hideyuki Komatsu：[e-mail]

### 文件与变量说明
#### 文件：Figure1_GTF-I_homology_model_data.py
**文件说明**：基于乳酸杆菌（Lactobacillus）GTF-180晶体结构构建的葡糖基转移酶（glucosyltransferase, GTF）-I同源建模数据。该文件可通过UCSF ChimeraX（https://www.cgl.ucsf.edu/chimerax/）进行可视化操作。

#### 文件：Figure3_GS_activity.csv
**文件说明**：以葡聚糖浓度为横坐标绘制的糖基转移活性数据集。
##### 变量说明
* Dextran1：对应GSdGBd3R、GSdGBd4RS、GSdGBd4RL、GSdGBd5R及DCP的葡聚糖浓度，单位为μg/mL
* GSdGBd3R：GSdGBd3R对应的糖基转移活性
* GSdGBd4RS：GSdGBd4RS的糖基转移活性……