1. Plasmid expression of Deinococcus radiodurans RecA confers UV-A protection to Escherichia coli with an inverse protein dose dependence, which does not exceed conspecific RecA protection.
- Author
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Chinchilla, Olga A. and LiCata, Vince J.
- Subjects
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DEINOCOCCUS radiodurans , *ESCHERICHIA coli , *PROTEINS , *HOMOLOGOUS recombination , *PROTEIN expression - Abstract
Low level expression in Escherichia coli of the RecA protein from the radiation resistant bacterium Deinococcus radiodurans protects a RecA deficient strain of E. coli from UV-A irradiation by up to ∼160% over basal UV-A resistance. The protection effect is inverse protein dose dependent: increasing the expression level of the D. radiodurans RecA (DrRecA) protein decreases the protection factor. This inverse protein dose dependence effect helps resolve previously conflicting reports of whether DrRecA expression is protective or toxic for E. coli. In contrast to the D. radiodurans protein effect, conspecific plasmid expression of E. coli RecA protein in RecA deficient E. coli is consistently protective over several protein expression levels, as well as consistently more protective to higher levels of UV-A exposure than that provided by the D. radiodurans protein. The results indicate that plasmid expression of D. radiodurans RecA can modestly enhance the UV resistance of living E. coli , but that the heterospecific protein shifts from protective to toxic as expression is increased. • Heterospectific expression of D. radiodurans RecA protein in E. coli confers modest organismal protection to UV-A damage. • The D. radiodurans RecA UV-A protection is inverse protein dose dependent: protection occurs at low but not high expression. • Conspecific expression of E. coli RecA protein in E. coli confers consistent but modest UV-A protection at all expression levels. • Conspecific RecA protein is more UV-A protective for E. coli cells than heterospecific D. radiodurans RecA protein. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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