Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan.
Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan.
Carbohydr Res. 2022 Nov;521:108670. doi: 10.1016/j.carres.2022.108670. Epub 2022 Sep 5.
The neutral polysaccharides LCPS-1 and LCPS-2 play functional roles in the cell wall of the lactic acid bacterium Lacticaseibacillus paracasei strain Shirota YIT 9029 (LcS; formerly Lactobacillus casei strain Shirota YIT 9029), which has long been used as a probiotic food product. Studies have shown that LCPS-1 is associated with the immunomodulatory functions of LcS. We hypothesized that the structure of LCPS-1 is crucial for elucidating the mechanism of action of LcS on host immune responses and aimed to solve the undetermined primary structure of LCPS-1. Our results showed that LCPS-1 has a molecular weight of >400 kDa and is composed of Glc, Rha, Gal, and GlcNAc, with a repeating structure. Using limited degradation reactions, including controlled Smith and deamination degradations, we obtained key fragments with low molecular weight. Subsequently, their structures were analyzed using NMR spectra and other analytical techniques. Further, we integrated the results for each key fragment to derive the complete structure of LCPS-1. Our results indicated that the most probable structure of LCPS-1 is composed of two types of units (X, Y), each with a basic structure of seven sugars in which the C2-position of Rha is substituted with an acetyl group. The structure of X is {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6] Glcβ1-} and that of Y is {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6)] GlcNAcβ1-}, which can be expressed as (XY). In this study, we identified the primary structure of LCPS-1, and our results may enable an improved understanding of the immunomodulatory abilities of LcS.
中性多糖 LCPS-1 和 LCPS-2 在乳酸乳球菌菌株 Shirota YIT 9029（LcS；以前称为干酪乳杆菌 Shirota YIT 9029）的细胞壁中发挥功能作用，该菌长期以来一直被用作益生菌食品。研究表明，LCPS-1 与 LcS 的免疫调节功能有关。我们假设 LCPS-1 的结构对于阐明 LcS 对宿主免疫反应的作用机制至关重要，并旨在解决 LCPS-1 未确定的一级结构。我们的结果表明，LCPS-1 的分子量>400 kDa，由 Glc、Rha、Gal 和 GlcNAc 组成，具有重复结构。使用包括受控 Smith 和脱氨降解在内的有限降解反应，我们获得了具有低分子量的关键片段。随后，使用 NMR 光谱和其他分析技术分析它们的结构。此外，我们将每个关键片段的结果整合起来，得出 LCPS-1 的完整结构。我们的结果表明，LCPS-1 的最可能结构由两种类型的单元（X、Y）组成，每个单元都具有七个糖的基本结构，其中 Rha 的 C2 位被乙酰基取代。X 的结构是 {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6] Glcβ1-}，Y 的结构是 {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6)] GlcNAcβ1-}，可以表示为 (XY)。在这项研究中，我们确定了 LCPS-1 的一级结构，我们的结果可能有助于更好地理解 LcS 的免疫调节能力。
