Abstract
Natural transformation is a mechanism for genetic exchange in many bacterial genera. It proceeds through the uptake of exogenous DNA and subsequent homology-dependent integration into the genome. In Streptococcus pneumoniae, this integration requires the ubiquitous recombinase, RecA, and DprA, a protein of unknown function widely conserved in bacteria. To unravel the role of DprA, we have studied the properties of the purified S. pneumoniae protein and its Bacillus subtilis ortholog (Smf). We report that DprA and Smf bind cooperatively to single-stranded DNA (ssDNA) and that these proteins both self-interact and interact with RecA. We demonstrate that DprA-RecA-ssDNA filaments are produced and that these filaments catalyze the homology-dependent formation of joint molecules. Finally, we show that while the Escherichia coli ssDNA-binding protein SSB limits access of RecA to ssDNA, DprA lowers this barrier. We propose that DprA is a new member of the recombination-mediator protein family, dedicated to natural bacterial transformation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacillus subtilis / enzymology
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Bacillus subtilis / genetics
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Bacillus subtilis / metabolism
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Cell Nucleus / enzymology
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Cell Nucleus / metabolism
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DNA, Bacterial / metabolism*
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DNA, Circular / metabolism
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DNA, Single-Stranded / metabolism*
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DNA, Superhelical / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Escherichia coli / enzymology
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism*
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Evolution, Molecular
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Exodeoxyribonucleases / metabolism
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Genomic Instability
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Nucleic Acid Conformation
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Protein Binding
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Rec A Recombinases / genetics
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Rec A Recombinases / metabolism*
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Recombinant Proteins / metabolism
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Recombination, Genetic
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Streptococcus pneumoniae / enzymology
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Streptococcus pneumoniae / genetics
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Streptococcus pneumoniae / metabolism
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Transformation, Bacterial*
Substances
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Bacterial Proteins
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DNA, Bacterial
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DNA, Circular
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DNA, Single-Stranded
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DNA, Superhelical
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DNA-Binding Proteins
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DprA protein, bacteria
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Escherichia coli Proteins
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Membrane Proteins
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Recombinant Proteins
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SSB protein, E coli
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Rec A Recombinases
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Exodeoxyribonucleases