γ- poly glutamic acid (γ-PGA), a high molecular weight polymer, is synthesized by microorganisms and secreted into the extracellular space. Due to its excellent performance, γ-PGA has been widely used in various fields, including food, biomedical and environmental fields. In this study, we screened natto samples for two strains of Bacillus subtilis N3378-2at and N3378-3At that produce γ-PGA. We then identified the γ-PGA synthetase gene cluster (PgsB, PgsC, PgsA, YwtC and PgdS), glutamate racemase RacE, phage-derived γ-PGA hydrolase (PghB and PghC) and exo-γ-glutamyl peptidase (GGT) from the genome of these strains. Based on these γ-PGA-related protein sequences from isolated Bacillus subtilis and 181 B. subtilis obtained from GenBank, we carried out genotyping analysis and classified them into types 1–5. Since we found B. amyloliquefaciens LL3 can produce γ-PGA, we obtained the B. velezensis and B. amyloliquefaciens strains from GenBank and classified them into types 6 and 7 based on LL3. Finally, we constructed evolutionary trees for these protein sequences. This study analyzed the distribution of γ-PGA-related protein sequences in the genomes of B. subtilis, B. velezensis and B. amyloliquefaciens strains, then the evolutionary diversity of these protein sequences was analyzed, which provided novel information for the development and utilization of γ-PGA-producing strains.

中文翻译：

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产γ-聚谷氨酸枯草芽孢杆菌基因组特征及相关功能基因

γ-聚谷氨酸（γ-PGA）是一种高分子量聚合物，由微生物合成并分泌到细胞外空间。由于其优异的性能，γ-PGA已广泛应用于各个领域，包括食品、生物医学和环境领域。在本研究中，我们筛选了纳豆样品中两种产生 γ-PGA 的枯草芽孢杆菌 N3378-2at 和 N3378-3At 菌株。然后我们从这些菌株的基因组。根据从GenBank获得的分离的枯草芽孢杆菌和181个枯草芽孢杆菌的γ-PGA相关蛋白序列，我们进行了基因分型分析，并将其分为1-5型。由于我们发现B. amyloliquefaciens LL3可以产生γ-PGA，因此我们从GenBank中获得了B. velezensis和B. amyloliquefaciens菌株，并根据LL3将其分为6型和7型。最后，我们为这些蛋白质序列构建了进化树。本研究分析了枯草芽孢杆菌、贝莱斯芽孢杆菌和解淀粉芽孢杆菌基因组中γ-PGA相关蛋白序列的分布，进而分析了这些蛋白序列的进化多样性，为开发利用提供了新的信息。 γ-PGA 生产菌株。