海洋细菌粪产碱菌J481中DMS趋化受体的鉴定

Identification of DMS receptors in the marine Alcaligenes faecalis J481

摘要:

【目的】β-二甲基巯基丙酸(β-dimethylsufoniopropionate，DMSP)是海洋环境中重要的含硫有机化合物，会被海洋中的微生物裂解并释放出挥发性气体二甲基硫醚(dimethylsulfide，DMS)。该反应的生物学意义尚不明确，前人曾有少量研究表明DMSP可能是趋化效应物。本研究旨在鉴定DMSP趋化作用中的信号分子以及该过程中的趋化受体基因。【方法】挖掘出基因组中含有甲基趋化受体蛋白结构域(methyl-accepting chemotaxis protein，MCP)的全部基因，并预测趋化受体蛋白的结构特征及功能。通过同源重组构建所有趋化受体的缺失突变株，并通过软琼脂平板实验观察趋化表型确定DMS的趋化受体。【结果】对不同化合物DMSP、DMS、丙烯酸进行鉴别后，明确趋化信号分子为DMS。从粪产碱菌(Alcaligenes faecalis)J481基因组中一共挖掘到8个潜在编码趋化受体蛋白的基因，分别构建对应的缺失突变株，并通过实验筛选出D6I95_17420基因为编码识别DMS的趋化受体蛋白基因。【结论】D6I95_17420基因为编码DMS的趋化受体蛋白的基因，为之后进一步阐明DMS作为信号分子在细胞内的调控作用奠定了基础。

Abstract:

[Objective] β-dimethylsulfoniopropionate (DMSP), an important sulfur-containing organic compound in the marine environment, is the main precursor to the climatically important gas dimethyl sulfide (DMS). DMS is released upon the bacterial catabolism of DMSP. The biological significance of this reaction is still unclear, and studies have shown that DMSP might be a chemoattractant. This study aims to identify the signal molecule in the chemotaxis of Alcaligenes faecalis J481 to DMSP and the receptor gene in this process. [Methods] All genes encoding methyl-accepting chemotaxis protein (MCP) were explored by genome mining, and the structures and functions of the chemotaxis receptors were predicted. The receptors-deleted mutants were developed by homologous recombination. The chemotactic phenotypes were observed based on the soft agar plate experiment and the chemotaxis receptors of DMS were determined. [Results] Through the test of DMSP, DMS, and acrylic acid, it was found that the signal molecule in the chemotaxis was DMS. A total of 8 potential genes encoding chemotaxis receptor proteins were found from the genome of J481, and D6I95_17420 was identified to encode the receptor protein of DMS. [Conclusion] D6I95_17420 encodes the chemotaxis receptor protein of DMS, which lays a foundation for further exploring the regulatory effect of DMS as a signal molecule in cells.