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Significance of Glutamate Racemase for the Viability and Cell Wall Integrity of Streptococcus iniae.

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اقرأ على الانترنت اقرأ أكثر حفظ في قائمتي
  • معلومة اضافية
    • المصدر:
      Publisher: MAIK Nauka/Interperiodica Country of Publication: United States NLM ID: 0376536 Publication Model: Print Cited Medium: Internet ISSN: 1608-3040 (Electronic) Linking ISSN: 00062979 NLM ISO Abbreviation: Biochemistry (Mosc) Subsets: MEDLINE
    • بيانات النشر:
      Publication: <2007->: Moscow : MAIK Nauka/Interperiodica
      Original Publication: New York, Consultants Bureau [etc.]
    • الموضوع:
      Cell Wall*/drug effects ; Cell Wall*/metabolism ; Microbial Viability*/drug effects; Amino Acid Isomerases/*metabolism ; Streptococcus iniae/*enzymology; Amino Acid Isomerases/antagonists & inhibitors ; Amino Acid Isomerases/genetics ; Hydrogen-Ion Concentration ; Metals, Heavy/pharmacology ; Mutation ; Streptococcus iniae/drug effects ; Streptococcus iniae/metabolism
    • نبذة مختصرة :
      Streptococcus iniae is a pathogenic and zoonotic bacterium responsible for human diseases and mortality of many fish species. Recently, this bacterium has demonstrated an increasing trend for antibiotics resistance, which has warranted a search for new approaches to tackle its infection. Glutamate racemase (MurI) is a ubiquitous enzyme of the peptidoglycan synthesis pathway that plays an important role in the cell wall integrity maintenance; however, the significance of this enzyme differs in different species. In this study, we knocked out the MurI gene in S. iniae in order to elucidate the role of glutamate racemase in maintaining cell wall integrity in this bacterial species. We also cloned, expressed, and purified MurI and determined its biochemical characteristics. Biochemical analysis revealed that the MurI gene in S. iniae encodes a functional enzyme with a molecular weight of 30 kDa, temperature optimum at 35°C, and pH optimum at 8.5. Metal ions, such as Cu2+, Mn2+, Co2+ and Zn2+, inhibited the enzyme activity. MurI was found to be essential for the viability and cell wall integrity of S. iniae. The optimal growth of the MurI-deficient S. iniae mutant can be achieved only by adding a high concentration of D-glutamate to the medium. Membrane permeability assay of the mutant showed an increasing extent of the cell wall damage with time upon D-glutamate starvation. Moreover, the mutant lost its virulence when incubated in fish blood. Our results demonstrated that the MurI knockout leads to the generation of S. iniae auxotroph with damaged cell walls.
    • الرقم المعرف:
      0 (Metals, Heavy)
      EC 5.1.1.- (Amino Acid Isomerases)
      EC 5.1.1.3 (glutamate racemase)
    • الموضوع:
      Date Created: 20200226 Date Completed: 20200401 Latest Revision: 20200401
    • الموضوع:
      20250114
    • الرقم المعرف:
      10.1134/S0006297920020121
    • الرقم المعرف:
      32093601