Organism | UniProt | Comment | Textmining |
---|---|---|---|
Porphyromonas gingivalis | Q7MTG0 | - |
- |
Porphyromonas gingivalis ATCC BAA-308 | Q7MTG0 | - |
- |
Porphyromonas gingivalis W83 | Q7MTG0 | - |
- |
Synonyms | Comment | Organism |
---|---|---|
SPI | - |
Porphyromonas gingivalis |
General Information | Comment | Organism |
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additional information | if an N-terminal glutamine residue is exposed as a result of proteolysis, e.g. signal peptide proteolysis by signal peptidase 1, this glutamine residue has a tendency to cyclize to diglutamate, with release of ammonia as a side product. The transamidation reaction is thought to initiate with nucleophilic attack of the alpha-amino group on the carbonyl group of the side chain carboxamide, followed by collapse of the oxyanion intermediate and protonation of the leaving epsilon-amino group. Glutamine cyclization to diglutamate can occur spontaneously. The reaction is facilitated by inorganic catalysts such as phosphate ions serving as the proton shuttle, or can be catalyzed enzymatically by glutaminyl cyclases (QCs) | Porphyromonas gingivalis |
physiological function | proteins that carry a type I signal peptide are released from their membrane anchored signal peptide by signal peptidase I (SPI). They can then remain in the periplasm, or be transported further. In Bacteroidetes, signal peptide cleavage exposes N-terminal glutamine residues in most signal peptidase I (SPI) substrates. The newly exposed glutamines are cyclized to pyroglutamate (also termed 5-oxoproline) residues. Porphyromonas gingivalis SPI substrates typically have a glutamine residue downstream of the SPI cleavage site. A Gln residue downstream of the SPI cleavage site affects RgpA, but not RgpB and Kgp gingipains secretion | Porphyromonas gingivalis |