Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Mol Sci. 2023 Oct 16;24(20):15210. doi: 10.3390/ijms242015210.
Cyclic di-GMP (c-di-GMP) is a second messenger of intracellular communication in bacterial species, which widely modulates diverse cellular processes. However, little is known about the c-di-GMP network in filamentous multicellular cyanobacteria. In this study, we preliminarily investigated the c-di-GMP turnover proteins in based on published protein data. Bioinformatics results indicate the presence of at least 149 potential turnover proteins in five subspecies. Some proteins are highly conserved in all tested , whereas others are specifically found only in certain subspecies. To further validate the protein catalytic activity, we constructed a riboswitch-based c-di-GMP expression assay system in and confirmed that a GGDEF domain protein, Adc11, exhibits potential diguanylate cyclase activity. Moreover, we also evaluated a protein with a conserved HD-GYP domain, Ahd1, the expression of which significantly improved the swimming ability of . Enzyme-linked immunosorbent assay also showed that overexpression of Ahd1 reduced the intracellular concentration of c-di-GMP, which is presumed to exhibit phosphodiesterase activity. Notably, meta-analyses of transcriptomes suggest that Adc11 and Ahd1 are invariable. Overall, this work confirms the possible existence of a functional c-di-GMP network in , which will provide support for the revelation of the biological function of the c-di-GMP system in .
环二鸟苷酸（c-di-GMP）是细菌细胞内通讯的第二信使，广泛调节多种细胞过程。然而，丝状多细胞蓝藻中的 c-di-GMP 网络知之甚少。在这项研究中，我们根据已发表的蛋白数据初步研究了 中的 c-di-GMP 周转蛋白。生物信息学结果表明，在五个 亚种中至少存在 149 种潜在的周转蛋白。一些蛋白在所有测试的 中高度保守，而另一些蛋白仅在某些亚种中特异性发现。为了进一步验证蛋白的催化活性，我们在 中构建了基于 riboswitch 的 c-di-GMP 表达检测系统，并证实了一个 GGDEF 结构域蛋白 Adc11 具有潜在的双鸟苷酸环化酶活性。此外，我们还评估了一个具有保守 HD-GYP 结构域的蛋白 Ahd1，其表达显著提高了 的游动能力。酶联免疫吸附测定还表明，Ahd1 的过表达降低了细胞内 c-di-GMP 的浓度，推测其具有磷酸二酯酶活性。值得注意的是，转录组的荟萃分析表明 Adc11 和 Ahd1 是不变的。总体而言，这项工作证实了 在功能上可能存在 c-di-GMP 网络，这将为揭示 c-di-GMP 系统在 中的生物学功能提供支持。
