RESUMEN
The transport of proteins at the cell surface of Bacteroidetes depends on a secretory apparatus known as type IX secretion system (T9SS). This machine is responsible for the cell surface exposition of various proteins, such as adhesins, required for gliding motility in Flavobacterium, S-layer components in Tannerella forsythia, and tooth tissue-degrading enzymes in the oral pathogen Porphyromonas gingivalis Although a number of subunits of the T9SS have been identified, we lack details on the architecture of this secretion apparatus. Here we provide evidence that five of the genes encoding the core complex of the T9SS are co-transcribed and that the gene products are distributed in the cell envelope. Protein-protein interaction studies then revealed that these proteins oligomerize and interact through a dense network of contacts.
Asunto(s)
Proteínas Bacterianas/metabolismo , Sistemas de Secreción Bacterianos/metabolismo , Porphyromonas gingivalis/metabolismo , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Sistemas de Secreción Bacterianos/análisis , Sistemas de Secreción Bacterianos/genética , Infecciones por Bacteroidaceae/microbiología , Cristalografía por Rayos X , Genes Bacterianos , Humanos , Porphyromonas gingivalis/química , Porphyromonas gingivalis/genética , Mapas de Interacción de Proteínas , Subunidades de Proteína/análisis , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismoRESUMEN
PorM is a membrane protein involved in the assembly of the type IX secretion system (T9SS) from Porphyromonas gingivalis, a major bacterial pathogen responsible for periodontal disease in humans. The periplasmic domain of PorM was overexpressed in Escherichia coli and purified. A fragment of the purified protein was obtained by limited proteolysis. Crystals of this fragment belonged to the tetragonal space group P4(3)2(1)2. Native and MAD data sets were recorded to 2.85 and 3.1â Å resolution, respectively, using synchrotron radiation.
