著者

石田 英子 大戸 梅治 清水 敏之

出版者

日本結晶学会

雑誌

日本結晶学会誌 (ISSN:03694585)

巻号頁・発行日

vol.59, no.2-3, pp.108-113, 2017-06-30 (Released:2017-07-01)

参考文献数

19

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Fertilization, the crucial step in sexual reproduction, requires the fusion of haploid sperm and egg to create a genetically distinct offspring. Despite many studies on mammalian fertilization, the molecular mechanisms underlining the membrane fusion remain largely unknown. At present, IZUMO1 on the sperm surface and JUNO on the egg surface are known as the only protein pair essential for fertilization. In this review, we focus on the crystal structures of human IZUMO1, JUNO and IZUMO1-JUNO complex. These structures reveal the molecular mechanism of mammalian gamete recognition, and provide information for development of non-hormonal contraceptive agents.

著者

丹治 裕美 大戸 梅治 清水 敏之

出版者

日本結晶学会

雑誌

日本結晶学会誌 (ISSN:03694585)

巻号頁・発行日

vol.55, no.5, pp.285-289, 2013-10-31 (Released:2013-11-01)

参考文献数

16

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The Toll-like receptors(TLRs)are a family of pattern-recognition receptors that recognize pathogen-associated molecular patterns and activate innate immune system. TLR8 is activated by single-stranded RNA or synthetic imidazoquinoline compounds. We determined the crystal structures of unliganded and liganded TLR8 to clarify signaling and activation mechanism of TLR8.TLR8 monomer was ring-shaped structure in which N- and C-termini interacted directly. Both in the unliganded and liganded forms, TLR8 formed m-shaped dimer in which two C termini converged in the middle. Ligands were located in the two equivalent positions in the dimerization interface related by the non-crystallographic two-fold axis. The C-termini of the two TLR8 protomers were separated by 53 Å in the unliganded form; whereas, C-termini of the two monomers were brought into close proximity(~30 Å)in the liganded form, which would enable the subsequent dimerization of the TIR domains and downstream signaling.