著者

前島 一博 城地 保昌 西野 吉則 高田 英昭 鎌田 福美 日原 さえら

出版者

一般社団法人 日本生物物理学会

雑誌

生物物理 (ISSN:05824052)

巻号頁・発行日

vol.53, no.1, pp.004-010, 2013 (Released:2013-01-29)

参考文献数

29

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How is 2-m-long genomic DNA organized into a mitotic chromosome or nucleus? The nucleosome fiber has long been assumed to be folded into a 30-nm chromatin fiber, and further helically folded larger fiber. However, when we observed frozen hydrated human mitotic cells using cryoelectron microscopy (cryo-EM), no higher-order structures including 30-nm chromatin fibers were found. To further investigate the bulk structure of mitotic chromosomes, we performed small-angle X-ray scattering (SAXS) at SPring-8. No structural feature larger than 11 nm was detected, even on a chromosome-diameter scale (~1 μm). We also found a similar scattering pattern in interphase nuclei of HeLa cells in the range up to ~275 nm. Our findings suggest a common structural feature in interphase and mitotic chromatins: compact and irregular folding of nucleosome fibers occurs without a 30-nm chromatin structure.

著者

西野 吉則 木村 隆志 鈴木 明大 城地 保昌 別所 義隆

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.1, pp.18-23, 2017-02-28 (Released:2017-03-07)

参考文献数

23

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X-ray free-electron lasers (XFELs) with femtosecond pulse duration offer an innovative solution to transcend the spatial resolution limitation in conventional X-ray imaging for biological samples and soft matters by clearing up the radiation damage problem using the “diffraction-before-destruction” strategy. Building on this strategy, the authors are developing a method to image solution sample under controlled environment, pulsed coherent X-ray solution scattering (PCXSS), using XFELs and phase retrieval algorithms in coherent diffractive imaging (CDI). This article describes the basics of PCXSS and examples of PCXSS measurement, for a living cell and self-assemblies of gold nanoparticles, performed by the authors using SACLA. An attempt toward the industrial application of PCXSS is also described.