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A Tandem Liquid Chromatography–Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus
Published on: March 28, 2017
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Native mass spectrometry identifies an alternative DNA-binding pathway for BirA from Staphylococcus aureus
Jiulia Satiaputra1,2, Louise M Sternicki1, Andrew J Hayes1,3
1School of Biological Sciences, University of Adelaide, Adelaide, South Australia, 5005, Australia.
Scientific Reports
|February 28, 2019
Summary
Staphylococcus aureus biotin retention protein A (BirA) binds DNA as a monomer, unlike E. coli BirA. This monomeric DNA binding allows for subsequent homodimerization on the DNA, a novel mechanism for bacterial transcriptional regulation.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Biotin is essential for Staphylococcus aureus survival and pathogenesis.
- Biotin homeostasis is regulated by biotin retention protein A (BirA), a bi-functional enzyme.
- BirA acts as a ligase and a transcriptional repressor, regulating genes involved in biotin metabolism.
Purpose of the Study:
- To elucidate the DNA binding pathway of S. aureus BirA (SaBirA).
- To compare the DNA binding mechanism of SaBirA with that of E. coli BirA (EcBirA).
Main Methods:
- Native mass spectrometry
- In vivo gene expression assays
- Site-directed mutagenesis
- Electrophoretic mobility shift assays (EMSA)
- Bioinformatic analysis
Main Results:
- SaBirA binds DNA as a monomer, independent of biotin and MgATP.
- SaBirA undergoes homodimerization on the DNA.
- This mechanism differs from the biotin-induced homodimerization prerequisite for DNA binding observed in EcBirA.
- The identified SaBirA DNA-binding mechanism is conserved across S. aureus strains.
Conclusions:
- S. aureus employs a distinct DNA binding mechanism for BirA compared to E. coli.
- SaBirA's ability to bind DNA as a monomer facilitates transcriptional regulation.
- This conserved mechanism highlights a potential target for antimicrobial strategies against S. aureus.
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