Kinase activity of the dgk gene product is involved in the virulence of Streptococcus mutans
| Autor: | Toru Takeshita, Takeshi kozuki, Yukie Shibata, Jan R. van der Ploeg, Yoshihisa Yamashita, Naoaki Saito, Miki Kawada-Matsuo, Yasuhito Shirai |
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| Přispěvatelé: | University of Zurich, Yamashita, Y |
| Rok vydání: | 2009 |
| Předmět: |
Diacylglycerol Kinase
Molecular Sequence Data Mutant 610 Medicine & health Biology Microbiology Streptococcus mutans Bacterial Proteins Streptococcal Infections Animals Humans Amino Acid Sequence Kinase activity Peptide sequence Sequence Deletion Diacylglycerol kinase chemistry.chemical_classification Virulence Kinase C-terminus 2404 Microbiology biology.organism_classification Rats Amino acid 10182 Institute of Oral Biology Biochemistry chemistry Acids |
| Zdroj: | Microbiology. 155:557-565 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/mic.0.023812-0 |
| Popis: | C-terminal deletion of the diacylglycerol kinase (Dgk) homologue of the cariogenic oral bacteriumStreptococcus mutansresulted in loss of aciduricity. To confirm the role of the C terminus of the Dgk homologue in aciduricity, various mutants ofS. mutansUA159 with a C-terminally truncated Dgk homologue were constructed. The deletion of one or two amino acid residues at the C terminus had no effect on the acid-tolerance properties of mutants. When further amino acid residues at the C terminus were removed, mutants became more acid-sensitive. The mutant with deletion of eight amino acid residues at the C terminus did not grow at pH 5.5, suggesting that the C-terminal tail of the Dgk homologue was indispensable for tolerance to acid stress inS. mutans. Kinase activity assays revealed that deletion of the C-terminal amino acids of Dgk led to a reduction of kinase activity for undecaprenol. A truncated mutant that had completely lost kinase activity was unable to grow at pH 5.5. These results suggest that the acid tolerance ofS. mutansis closely related to kinase activity of the Dgk homologue. Additionally, thedgkdeletion mutant exhibited markedly reduced levels of smooth-surface carious lesions in pathogen-free rats, despite there being no difference between the mutant and the parental organism in the extent of total smooth surface plaque. The results suggest that Dgk activity may play a direct role in the virulence ofS. mutans. |
| Databáze: | OpenAIRE |
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