탄저균에서 알라몬 합성효소 과발현에 관한 연구

Abstract

Bacillus anthracis, the agent of anthrax, has a biphasic life cycle including spores and vegetative cells. Such a morphological transition is triggered by nutrient starvation or other environmental stresses. Interestingly, a recent study demonstrated the presence of a functional RelA/SpoT homologue in B. anthracis, which is essential for the production of alarmone (guanosine tetraphosphate, ppGpp), the key effector molecule for stringent response under nutrient starvation or stressful conditions. The experiments in this study were attempted to investigate the effect of ppGpp on B. anthracis. Then, it was found that BAS4302 was a putative RelA/SpoT homologue of B. anthracis Sterne. The experimental analyses demonstrated that (i) an N-terminal His-tagged BAS4302 (His-BAS4302) could restore a typical ppGpp-dependent growth defect on minimal glucose media and (ii) the secretome profiles used in 2-DE analysis were altered by overexpression of His-BAS4302. Among the 66 protein spots differentially expressed by >1.5 folds, a total of 28 proteins was further identified by MALDI-TOF analysis, including Dps2, arginase, collagenase, peptidase, and collagen adhesin. The result implies that the stringent response alters the secretome profile in B. anthracis.