Eun-Young Lee1, Joo Young Bang2, Gun Wook Park3, Dong-Sic Choi1, Ji Seoun Kang1, Hyun-Jung Kim1, Kyong-Su Park1, Jeong-Ok Lee1, Yoon-Keun Kim1, Kyung-Hoon Kwon3, Kwang-Pyo Kim2 and Yong Song Gho Professor1,*
1 Department of Life Science and Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
2 Institute of Biomedical Science and Technology, Department of Molecular Biotechnology, Konkuk University, Seoul, Republic of Korea
3 Mass Spectrometer Development Team, Korea Basic Science Institute, Daejeon, Republic of Korea
Gram-negative bacteria constitutively secrete native outer membrane vesicles (OMVs) into the extracellular milieu. Although recent progress in this area has revealed that OMVs are essential for bacterial survival and pathogenesis, the mechanism of vesicle formation and the biological roles of OMVs have not been clearly defined. Using a proteomics approach, we identified 141 protein components of Escherichia coli-derived native OMVs with high confidence; two separate analyses yielded identifications of 104 and 117 proteins, respectively, with 80 proteins overlapping between the two trials. In the group of identified proteins, the outer membrane proteins were highly enriched, whereas inner membrane proteins were lacking, suggesting that a specific sorting mechanism for vesicular proteins exists. We also identified proteins involved in vesicle formation, the removal of toxic compounds and attacking phage, and the elimination of competing organisms, as well as those involved in facilitating the transfer of genetic material and protein to other bacteria, targeting host cells, and modulating host immune responses. This study provides a global view of native bacterial OMVs. This information will help us not only to elucidate the biogenesis and functions of OMV from nonpathogenic and pathogenic bacteria but also to develop vaccines and antibiotics effective against pathogenic strains.
Keywords : E. coli DH5α; Microvesicles; Outer membrane vesicles; Tandem mass spectrometry; Vaccine