scholarly journals Dipeptidyl‐peptidases: Key enzymes producing entry forms of extracellular proteins in asaccharolytic periodontopathic bacterium Porphyromonas gingivalis

2020 ◽  
Author(s):  
Takayuki K. Nemoto ◽  
Yuko Ohara Nemoto
Keyword(s):  
Porphyromonas Gingivalis ◽  
Extracellular Proteins ◽  
Key Enzymes ◽  
Dipeptidyl Peptidases

scholarly journals Dynamic oligopeptide acquisition by the RagAB transporter from Porphyromonas gingivalis

2019 ◽  
Author(s):  
Mariusz Madej ◽  
Joshua B. R. White ◽  
Zuzanna Nowakowska ◽  
Shaun Rawson ◽  
Carsten Scavenius ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Direct Evidence ◽  
Inflammatory Diseases ◽  
Extracellular Proteins ◽  
Substrate Selectivity ◽  
Binding Studies ◽  
Uptake Mechanism ◽  
X Ray ◽  
Cryo Electron Microscopy ◽  
Binding Surface

AbstractPorphyromonas gingivalis, an asaccharolytic Bacteroidetes, is a keystone pathogen in human periodontitis that may also contribute to the development of other chronic inflammatory diseases, such as rheumatoid arthritis, cardiovascular disease and Alzheimer’s disease. P. gingivalis utilizes protease-generated peptides derived from extracellular proteins for growth, but how those peptides enter the cell is not clear. Here we identify RagAB as the outer membrane importer for peptides. X-ray crystal structures show that the transporter forms a dimeric RagA2B2 complex with the RagB substrate binding surface-anchored lipoprotein forming a closed lid on the TonB-dependent transporter RagA. Cryo-electron microscopy structures reveal the opening of the RagB lid and thus provide direct evidence for a “pedal bin” nutrient uptake mechanism. Together with mutagenesis, peptide binding studies and RagAB peptidomics, our work identifies RagAB as a dynamic OM oligopeptide acquisition machine with considerable substrate selectivity that is essential for the efficient utilisation of proteinaceous nutrients by P. gingivalis.

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