Mycobacterium tuberculosis mtrA merodiploid strains with point mutations in the signal-receiving domain of MtrA exhibit growth defects in nutrient broth
| Autor: | Krishna Sarva, Murty V. V. S. Madiraju, Malini Rajagopalan, Maha Al Zayer, Renata Dziedzic, Dorota L. Stankowska |
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| Rok vydání: | 2011 |
| Předmět: |
Mutant
Plasma protein binding Biology Article Bacterial Proteins Point Mutation Asparagine Amino Acids Phosphorylation Promoter Regions Genetic Molecular Biology Alanine Antigens Bacterial Autophosphorylation RNA-Binding Proteins Gene Expression Regulation Bacterial Mycobacterium tuberculosis Protein Structure Tertiary Response regulator Biochemistry ATP-Binding Cassette Transporters Signal transduction Acyltransferases Protein Binding Signal Transduction Transcription Factors |
| Zdroj: | Plasmid. 65:210-218 |
| ISSN: | 0147-619X |
| DOI: | 10.1016/j.plasmid.2011.01.002 |
| Popis: | The genetic and biochemical aspects of the essential Mycobacteriumtuberculosis MtrAB two-component regulatory signal transduction (2CRS) system have not been extensively investigated. We show by bacterial two-hybrid assay that the response regulator (RR) MtrA and the sensor kinase MtrB interact. We further demonstrate that divalent metal ions [Mg²+, Ca²+ or both] promote MtrB kinase autophosphorylation activity, but only Mg²+ promotes phosphotransfer to MtrA. Replacement of the conserved aspartic acid residues at positions 13 and 56 with alanine (D13A), glutamine (D56E) or asparagine (D56N) prevented MtrA phosphorylation, indicating that these residues are important for phosphorylation. The MtrA(D56E) and MtrA(D13A) proteins bound to the promoter of fbpB, the gene encoding antigen 85B protein, efficiently in the absence of phosphorylation, whereas MtrA(D56N) did not. We also show that M.tuberculosismtrA merodiploids overproducing MtrA(D13A), unlike cells overproducing wild-type MtrA, grow poorly in nutrient broth and show reduced expression of fbpB. These latter findings are reminiscent of a phenotype associated with MtrA overproduction during intramacrophage growth. Our results suggest that MtrA(D13A) behaves like a constitutively active response regulator and that further characterization of mtrA merodiploid strains will provide valuable clues to the MtrAB system. |
| Databáze: | OpenAIRE |
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