The Acinetobacter regulatory UmuDAb protein cleaves in response to DNA damage with chimeric LexA/UmuD characteristics
| Autor: | Janelle M. Hare, Alison N. Grice, Kasandra V. Lambert, Alexander E. Hare, Sabal Adhikari |
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| Rok vydání: | 2012 |
| Předmět: |
DNA damage
Ultraviolet Rays Mutant Molecular Sequence Data DNA-Directed DNA Polymerase Cleavage (embryo) Microbiology Article chemistry.chemical_compound Bacterial Proteins Transcription (biology) Genetics Escherichia coli Amino Acid Sequence SOS response Molecular Biology Polymerase biology Acinetobacter Escherichia coli Proteins Serine Endopeptidases Gene Expression Regulation Bacterial Molecular biology Rec A Recombinases chemistry biology.protein Repressor lexA Protein Processing Post-Translational Sequence Alignment DNA DNA Damage |
| Zdroj: | FEMS microbiology letters. 334(1) |
| ISSN: | 1574-6968 |
| Popis: | In the DNA damage response of most bacteria, UmuD forms part of the error-prone (UmuD′2)C polymerase V and is activated for this function by self-cleavage after DNA damage. However, the umuD homolog ( umuDAb ) present throughout the Acinetobacter genus encodes an extra N-terminal region, and in Acinetobacter baylyi , regulates transcription of DNA damage–induced genes. UmuDAb expressed in cells was correspondingly larger (24 kDa) than the Escherichia coli UmuD (15 kDa). DNA damage from mitomycin C or UV exposure caused UmuDAb cleavage in both E. coli wild-type and ΔumuD cells on a timescale resembling UmuD, but did not require UmuD. Like the self-cleaving serine proteases LexA and UmuD, UmuDAb required RecA for cleavage. This cleavage produced a UmuDAb′ fragment of a size consistent with the predicted cleavage site of Ala83–Gly84. Site-directed mutations at Ala83 abolished cleavage, as did mutations at either the Ser119 or Lys156 predicted enzymatic residues. Co-expression of the cleavage site mutant and an enzymatic mutant did not allow cleavage, demonstrating a strictly intramolecular mechanism of cleavage that more closely resembles the LexA-type repressors than UmuD. These data show that UmuDAb undergoes a post-translational, LexA-like cleavage event after DNA damage, possibly to achieve its regulatory action. |
| Databáze: | OpenAIRE |
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