Overexpression of an antimicrobial peptide derived from C. elegans using an aggregation-prone protein coexpression system.
Antibacterial factor 2 (ABF-2) is a 67-residue antimicrobial peptide derived from the nematode Caenorhabditis elegans. Although it has been reported that ABF-2 exerts in vitro microbicidal activity against a range of bacteria and fungi, the structure of ABF-2 has not yet been solved. To enable structural studies of ABF-2 by NMR spectroscopy, a large amount of isotopically labeled ABF-2 is essential. However, the direct expression of ABF-2 in Escherichia coli is difficult to achieve due to its instability. Therefore, we applied a coexpression method to the production of ABF-2 in order to enhance the inclusion body formation of ABF-2. The inclusion body formation of ABF-2 was vastly enhanced by coexpression of aggregation-prone proteins (partner proteins). By using this method, we succeeded in obtaining milligram quantities of active, correctly folded ABF-2. In addition, 15 N-labeled ABF-2 and a well-dispersed heteronuclear single quantum coherence (HSQC) spectrum were also obtained successfully. Moreover, the effect of the charge of the partner protein on the inclusion body formation of ABF-2 in this method was investigated by using four structurally homologous proteins. We concluded that a partner protein of opposite charge enhanced the formation of an inclusion body of the target peptide efficiently.
Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan. aizawa@mail.sci.hokudai.ac.jp.
Satoshi
S
Tomisawa
Eri
E
Hojo
Yoshitaka
Y
Umetsu
Shinya
S
Ohki
Yusuke
Y
Kato
Mitsuhiro
M
Miyazawa
Mineyuki
M
Mizuguchi
Masakatsu
M
Kamiya
Yasuhiro
Y
Kumaki
Takashi
T
Kikukawa
Keiichi
K
Kawano
Makoto
M
Demura
Tomoyasu
T
Aizawa