EhV-ATPase is an ATP-driven Na+ pump in the eubacteria Enterococcus hirae (Eh). Here, we present the first entire structure of detergent-solubilized EhV-ATPase by single-particle cryo-electron microscopy (cryo-EM) using Zernike phase plate. The cryo-EM map dominantly showed one of three catalytic conformations in this rotary enzyme. To further stabilize the originally heterogeneous structure caused by the ATP hydrolysis states of the V1-ATPases, a peptide epitope tag system was adopted, in which the inserted peptide epitope sequence interfered with rotation of the central rotor by binding the Fab. As a result, the map unexpectedly showed another catalytic conformation of EhV-ATPase. Interestingly, these two conformations identified with and without Fab conversely coincided with those of the minor state 2 and the major state 1 of Thermus thermophilus V/A-ATPase, respectively. The most prominent feature in EhV-ATPase was the off-axis rotor, where the cytoplasmic V1 domain was connected to the transmembrane Vo domain through the off-axis central rotor. Furthermore, compared to the structure of ATP synthases, the larger size of the interface between the transmembrane a-subunit and c-ring of EhV-ATPase would be more advantageous for active ion pumping.

We report on the phase-matching properties of borate crystals of LiB3O5 (LBO), CsB3O5 (CBO), and CsLiB6O10 (CLBO) in vacuum–ultraviolet (VUV) light generation at around 190 nm. A new phase-matching property in the VUV spectral range for CBO grown from a self-flux solution was found to have better agreement with new Sellmeier's equations developed in our laboratory. A 189 nm output of 11.4 mW was produced in a CLBO with a conversion efficiency of 7.3% from 213 nm input. CLBO is suitable for VUV light generation around 190 nm with the present laser system.

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The phase-matching properties of borate crystals were investigated for vacuum ultraviolet light generation. A 189-nm output of 8.2 mW was observed with CLBO while new phase-matching property of CBO was found.