Extracellular proteome changes of Deinococcus radiodurans under gamma-irradiation stress conditions.

To analysis the change of Deinococcus radiodurans extracellular proteins recovering from gamma-irradiation, we examined extracellular proteome changes using two-dimensional polyacrylamide gel electrophoresis. Twenty-six spots on the gel of irradiated sample were showed significant changes compared with spots on the control gel. Using peptide mass fingerprinting via matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS), 21 different proteins could be distinguished. Among the identified proteins, seven are classified in transport and metabolism, and one is involved in intracellular trafficking and secretion. The other proteins are known to several functions in the cytosol. Most of the proteins have not previously been reported to be relevant to radioresistance. These results imply that the transmembrane transportation is involved in and contributes to the radioresistance in this organism.