Surface location of HPr, a phosphocarrier of the phosphoenolpyruvate: sugar phosphotransferase system in Streptococcus suis
| Autor: | Denis Brochu, Mario Jacques, J. D. Dubreuil, Christian Vadeboncoeur, Michel Frenette |
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| Rok vydání: | 1996 |
| Předmět: |
Streptococcus suis
Molecular Sequence Data macromolecular substances Phosphocarrier protein Microbiology chemistry.chemical_compound Bacterial Proteins Species Specificity Amino Acid Sequence Microscopy Immunoelectron Phosphoenolpyruvate Sugar Phosphotransferase System chemistry.chemical_classification Methionine Sequence Homology Amino Acid Molecular mass biology Cell Membrane Streptococcus PEP group translocation biology.organism_classification Molecular biology Molecular Weight Streptococcus salivarius Enzyme chemistry Biochemistry biology.protein bacteria Phosphoenolpyruvate carboxykinase |
| Zdroj: | Microbiology. 142:837-843 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/00221287-142-4-837 |
| Popis: | HPr is a low-molecular-mass phosphocarrier protein of the bacterial phosphoenolpyruvate (PEP): sugar phosphotransferase system (PTS) found in the cytoplasm or associated with the inner surface of the cytoplasmic membrane. Treatment of Streptococcus suis cells with a Sorvall Omnimixer, a technique used to extract cell surface components, resulted in the extraction of a major protein with a molecular mass of 9 kDa. Several lines of evidence suggested that this protein was HPr: (i) the S. suis protein showed homology over the first 35 N-terminal amino acid residues with the HPrs of Streptococcus salivarius and Streptococcus mutans, including the signature sequence for the site of PEP-dependent phosphorylation; (ii) it cross-reacted with the S. salivarius anti-HPr antibody preparation; (iii) it could be phosphorylated by enzyme 1 at the expense of PEP, and by a membrane-associated kinase at the expense of ATP; and (iv) it possessed phosphocarrier activity when used as a source of HPr in an in vitro PTS assay. The data suggested that a portion of the cellular HPr is associated with the external cell surface in S. suis, a result that was confirmed by immunogold electron microscopy. The cellular HPr of S. suis consisted of two forms that could be distinguished by the presence or the absence of the N-terminal methionine. Amino acid sequence analysis indicated that the cell-surface-associated HPr of S. suis lacked the N-terminal methionine residue. |
| Databáze: | OpenAIRE |
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