On the ionization energy of CF3SF5 in the valence region measured by angle-resolved photoelectron spectroscopy

Ionization energies for valence electrons of CF3SF5 were measured in the 12-35 eV region by means of angle-resolved photoelectron spectroscopy. The observed ionization energies were basically consistent with previous ones measured by threshold photoelectron and HeI photoelectron spectroscopy, and the ionization levels at 22.60, 26.92 and 27.86 eV were newly observed. Asymmetry parameter derived at hν = 684.7 eV was a constant of β = 1.02 ± 0.04 in the ionization energy lower than 20 eV, suggesting that lone pair electron of F atom is probably released through 2p → εd like electron emission. Characters of the 22 valence bands were elucidated with the help of ab initio calculations and of the nature of valence orbitals for CF4 and SF

Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19–deficient mice

Tight junction (TJ)–like structures have been reported in Schwann cells, but their molecular composition and physiological function remain elusive. We found that claudin-19, a novel member of the claudin family (TJ adhesion molecules in epithelia), constituted these structures. Claudin-19–deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits. Electrophysiological analyses showed that the claudin-19 deficiency affected the nerve conduction of peripheral myelinated fibers. Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons. These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological “sealing” function of Schwann cells

Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin

X線自由電子レーザーを用いて、光照射によるチャネルロドプシンの構造変化の過程を捉えることに成功. 京都大学プレスリリース. 2021-03-26.Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore