Microbiota-Host Interactions and Clostridia Research Group, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile.
ANID-Millennium Science Initiative Program, Millennium Nucleus in the Biology of the Intestinal Microbiota, Santiago, Chile.
mSphere. 2020 Nov 18;5(6):e01065-20. doi: 10.1128/mSphere.01065-20.
is an obligately anaerobic, spore-forming, Gram-positive pathogenic bacterium that is considered the leading cause of nosocomial diarrhea worldwide. Recent studies have attempted to understand the biology of the outermost layer of spores, the exosporium, which is believed to contribute to early interactions with the host. The fundamental role of the cysteine-rich proteins CdeC and CdeM has been described. However, the molecular details behind the mechanism of exosporium assembly are missing. The underlying mechanisms that govern exosporium assembly in remain poorly studied, in part due to difficulties in obtaining pure soluble recombinant proteins of the exosporium. In this work, we observed that CdeC was able to form organized inclusion bodies (IBs) in filled with lamella-like structures separated by an interspace of 5 to 15 nm; however, CdeC expression in an strain with a more oxidative environment led to the loss of the lamella-like organization of CdeC IBs. Additionally, dithiothreitol (DTT) treatment of CdeC inclusion bodies released monomeric soluble forms of CdeC. Deletions in different portions of CdeC did not affect CdeC's ability to aggregate and form oligomers stable under denaturation conditions but affected CdeC's self-assembly properties. Overall, these observations have important implications in further studies elucidating the role of CdeC in the exosporium assembly of spores. The endospore of is the vehicle for transmission and persistence of the pathogen, and, specifically, the exosporium is the first contact between the host and the spore. The underlying mechanisms that govern exosporium assembly in remain understudied, in part due to difficulties in obtaining pure soluble recombinant proteins of the exosporium. Understanding the exosporium assembly's molecular bases may be essential to developing new therapies against infection.
是一种专性厌氧、孢子形成、革兰氏阳性的致病性细菌，被认为是全球医院获得性腹泻的主要原因。最近的研究试图了解孢子最外层——外孢子的生物学特性，据信外孢子有助于与宿主的早期相互作用。富含半胱氨酸的蛋白质 CdeC 和 CdeM 的基本作用已经被描述。然而，外孢子组装机制的分子细节仍然缺失。由于难以获得纯的可溶性重组 外孢子蛋白， 外孢子组装的潜在机制在很大程度上仍未得到研究。在这项工作中，我们观察到 CdeC 能够在充满类似薄片结构的隔室中形成有组织的包涵体（IBs），这些隔室之间的间隔为 5 到 15nm；然而，在具有更氧化环境的 菌株中表达 CdeC 导致 CdeC IBs 的薄片样组织丢失。此外，DTT 处理 CdeC 包涵体释放出单体可溶性形式的 CdeC。CdeC 不同部分的缺失不影响 CdeC 聚集和形成在变性条件下稳定的寡聚物的能力，但影响 CdeC 的自组装特性。总的来说，这些观察结果对进一步阐明 CdeC 在 孢子外孢子组装中的作用具有重要意义。 的内孢子是病原体传播和持续存在的载体，特别是外孢子是宿主与孢子的第一次接触。 外孢子组装的潜在机制在很大程度上仍未得到研究，部分原因是难以获得纯的可溶性重组 外孢子蛋白。了解外孢子组装的分子基础可能对开发针对 感染的新疗法至关重要。
