Identification of stringent response-related and potential serological proteins released from Bacillus anthracis overexpressing the RelA/SpoT homolog, Rsh Bant.
RelA and SpoT synthesize ppGpp, a key effector molecule that facilitates the adaptation of bacteria to nutrient starvation and other stresses, known as the stringent response. To investigate the role of Rsh Bant , a putative RelA/SpoT homolog (encoded by BAS4302) in Bacillus anthracis, we examined the alteration of the secretome profiles after the overexpression of a functional His-Rsh Bant protein in the B. anthracis strain Sterne at the stationary growth phase. In the ppGpp-deficient E. coli mutant strain CF1693, overexpression of Rsh Bant restored a ppGpp-dependent growth defect on minimal glucose media. The secretome profiles obtained using a two-dimensional electrophoresis (2-DE) analysis were altered by overexpression of Rsh Bant in B. anthracis. Among the 66 protein spots differentially expressed >1.5-fold, the 29 proteins were abundant for further identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Functional categorization of those proteins implicated their involvement in various biological activities. Taken together, our results imply that overexpression of a functional His-Rsh Bant can lead to the increased levels of intracellular ppGpp in B. anthracis, resulting in the significant changes in its secretome profiling. The stringent response-controlled proteins identified are likely useful as potential targets for serodiagnostic applications.
Department of Molecular and Life Sciences, Hanyang University, 1271, Ansan, 426-791, Gyeonggi-do, Republic of Korea.
Se Kye
SK
Kim
Moon Kyoo
MK
Park
Sang Hoon
SH
Kim
Kwang Gun
KG
Oh
Kyoung Hwa
KH
Jung
Chong-Hae
CH
Hong
Jang W
JW
Yoon
Young Gyu
YG
Chai
D001408:Bacillus anthracis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D015180:Electrophoresis, Gel, Two-Dimensional; D001277:GTP Pyrophosphokinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D040901:Proteomics
D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D001277:GTP Pyrophosphokinase