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

Abstract

In order to examine radiation-induced proteins in an extremely radio-resistant bacterium, it became possible<br />to perform comparative proteomic analysis on radio-resistance Bacillus megaterium WHO as a wildtype<br />strain for the first time. Variation in cellular proteins profiles of the Bacillus megaterium WHO after 5<br />KGy γ-irradiation were analyzed by two-dimensional poly acryl amide gel electrophoresis and silver staining.<br />Although many spots were decreased in density, our primary focus was on the induced spots. The<br />expression level of 48 protein spots showed significant increase under radiation stress. Of these spots, 45<br />were 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 exhibited<br />various interesting cellular functions including: (i) transcription (ii) translation (iii) signal transduction (iv) carbohydrate transport and metabolism (v) energy production and conversion (vi) nucleotide transport and<br />metabolism (vii) posttranslational modification, protein turnover and chaperones (viii) DNA replication, recombination and repair (ix) bacterial general stress response and (iix) different and some still unknown<br />functions. The appearance of four spots (24, 27, 30 and 36) in response to γ-irradiation was the distinct<br />result of present study. These proteins appear to mediate processes related to ionizing radiation resistance<br />and clearly demonstrate that Bacillus megaterium WHO, significantly has mechanisms contribute to the<br />ionizing radiation resistance.