Comparative proteomics analysis of a novel g-radiation-resistant bacterium wild-type Bacillus megaterium strain WHO DQ973298 recovering from 5 KGy g-irradiation

In order to examine radiation-induced proteins in an extremely radio-resistant bacterium, it became possibleto perform comparative proteomic analysis on radio-resistance Bacillus megaterium WHO as a wildtypestrain for the first time. Variation in cellular proteins profiles of the Bacillus megaterium WHO after 5KGy γ-irradiation were analyzed by two-dimensional poly acryl amide gel electrophoresis and silver staining.Although many spots were decreased in density, our primary focus was on the induced spots. Theexpression level of 48 protein spots showed significant increase under radiation stress. Of these spots, 45were identified with MALDI TOF-TOF (peptide mass fingerprinting using matrix-assisted laser desorption/ionization time of flight mass spectrometry) after tryptic in-gel digestion. These proteins exhibitedvarious interesting cellular functions including: (i) transcription (ii) translation (iii) signal transduction (iv) carbohydrate transport and metabolism (v) energy production and conversion (vi) nucleotide transport andmetabolism (vii) posttranslational modification, protein turnover and chaperones (viii) DNA replication, recombination and repair (ix) bacterial general stress response and (iix) different and some still unknownfunctions. The appearance of four spots (24, 27, 30 and 36) in response to γ-irradiation was the distinctresult of present study. These proteins appear to mediate processes related to ionizing radiation resistanceand clearly demonstrate that Bacillus megaterium WHO, significantly has mechanisms contribute to theionizing radiation resistance.