Abstract

Protein phosphorylation on tyrosine has been demonstrated to occur in a wide array of bacterial species and appears to be ubiquitous among prokaryotes. InDeinococcus radiodurans, after the predicted protein-tyrosine phosphatase (PTP) gene DR2161 was deleted, the radiation resistance of the bacterium changed a little. The natural resistance-associated macrophage protein gene DR1709 was the possible target of PTP. But the radio resistance of the double mutant (DR1709 and DR2161 that were deleted) was almost the same as that of M1709. When the strain protease secretion was measured, the clearing area of M2161 was smaller than that of the wild type. But the protease secretion of the double mutant was similar to that of M1709. The influence on the bacterium DR2161, that was deleted seemed to have been covered by DR1709 being disrupted. The four strains (the wild type, M1709, M2161 and the double mutant) sensitivity to high concentrate of Mn²⁺ and Fe²⁺ were very similar, showing that they had similar resistance to high concentrate of Mn²⁺ or Fe²⁺. In liquid defined minimal medium (DMM) with 200 nM Mn, M1709 and the double mutant almost can not grow. But in DMM with 200 nM Fe, the two strains grew as quickly as the wild type. M1709 reaction to low concentrate of Mn²⁺ and Fe²⁺ was not affected by DR2161. The expression of DR1709 was not regulated by DR2161.

Key words: Deinococcus radiodurans, protein-tyrosine phosphatase, natural resistance-associated macrophage protein, DR1709, DR2161.