SAAV2152 is a single-stranded DNA binding protein: the third SSB in Staphylococcus aureus

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Single-stranded DNA-binding proteins (SSBs) are essential for DNA metabolism in bacteria.
• While E. coli has one SSB (EcSSB), other bacteria possess multiple SSBs, such as SsbA and SsbB in some species.

Purpose of the Study:

• To identify and characterize novel SSB-like proteins in Staphylococcus aureus.
• To investigate the DNA-binding properties and functional characteristics of the newly identified protein, designated SaSsbC.

Main Methods:

• Sequence analysis and homology modeling to predict protein structure.
• Electrophoretic mobility shift assays (EMSA) to assess ssDNA binding.
• Mutational analysis to identify key residues for DNA binding.
• Enzyme activity assays and inhibitor studies.

Main Results:

• A third SSB-like protein, SaSsbC (SAAV2152), was identified in S. aureus, sharing sequence homology with known SSBs.
• SaSsbC binds to single-stranded DNA (ssDNA) and possesses critical residues for this interaction, analogous to EcSSB.
• SaSsbC does not stimulate the activity of SaPriA, unlike EcSSB's effect on EcPriA.
• The SaSsbA inhibitor NSC5426 demonstrated inhibitory activity against SaSsbC's ssDNA binding.

Conclusions:

• SAAV2152 is characterized as a novel SSB protein in S. aureus.
• SaSsbC's DNA-binding mechanism involves conserved residues, but its functional interactions may differ from EcSSB.
• Further research is needed to elucidate the precise physiological role of SaSsbC in S. aureus DNA metabolism.