[2P-1] Poster 2 (2P-01ー2P-37)

[2P-19(YSA-6)] Translocational unfolding of binary toxin produced by Clostridium perfringens

^○Tomohito Yamada¹, Toru Yoshida^1,2, Akihiro Kawamoto³, Kaoru Mitsuoka⁴, Kenji Iwasaki^3,5, Hideaki Tsuge^1,6,7 (1.Faculty of Life Sciences Kyoto Sangyo University, 2.Department of Chemical and Biological Sciences, Faculty of Science, Japan Womens University, 3.Institute for Protein Research, Osaka University, 4.Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 5.Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 6.Institute for Protein Dynamics, Kyoto Sangyo University, 7.Center for Molecular Research in Infectious Diseases, Kyoto Sangyo University)

Binary toxin is bacterial toxin which is composed of enzymatic component and membrane binding component. Enzymatic component is thought to pass through membrane spanning β-barrel formed by membrane binding component oligomer. It is known that there is narrow clamp with a diameter of 6 angstrom which is smaller than diameter of α-helix. To complete the translocation, enzymatic component need be unfolded or the narrow clamp need expand for larger diameter but the mechanism was not revealed. Binary toxin is classified into two groups by the amino acid sequence difference in enzymatic component. In contrast, because membrane binding component is highly conserved between the two groups, it is thought that translocational mechanism is same between them. Thus, studying with comparison in both binary toxin groups is crucially important. We determined the structure of iota toxin (Ib-pore and Ia-bound Ib-pore) produced by Clostridium perfringens using cryo-EM single particle analysis. Comparing different group binary toxin between iota toxin and already reported anthrax binary toxin provided us new findings related in intoxication mechanism. I am going to present the findings with comparison of binary toxins which were reported in this few year.