Epidemiological Features of Human Norovirus Genotypes before and after COVID-19 Countermeasures in Osaka, Japan.

We investigated the molecular epidemiology of human norovirus (HuNoV) in all age groups using samples from April 2019 to March 2023, before and after the COVID-19 countermeasures were implemented. GII.2[P16] and GII.

Crystal structure of the lipid flippase MurJ in a "squeezed" form distinct from its inward- and outward-facing forms.

The bacterial peptidoglycan enclosing the cytoplasmic membrane is a fundamental cellular architecture. The integral membrane protein MurJ plays an essential role in flipping the cell wall building block Lipid II across the cytoplasmic membrane for peptidoglycan biosynthesis. Previously reported crystal structures of MurJ have elucidated its V-shaped inward- or outward-facing forms with an internal cavity for substrate binding.

Crystal structure of a YeeE/YedE family protein engaged in thiosulfate uptake.

We have demonstrated that a bacterial membrane protein, YeeE, mediates thiosulfate uptake. Thiosulfate is used for cysteine synthesis in bacteria as an inorganic sulfur source in the global biological sulfur cycle. The crystal structure of YeeE at 2.

Structural Basis of Sarco/Endoplasmic Reticulum Ca-ATPase 2b Regulation via Transmembrane Helix Interplay.

Sarco/endoplasmic reticulum (ER) Ca-ATPase 2b (SERCA2b) is a ubiquitously expressed membrane protein that facilitates Ca uptake from the cytosol to the ER. SERCA2b includes a characteristic 11 transmembrane helix (TM11) followed by a luminal tail, but the structural basis of SERCA regulation by these C-terminal segments remains unclear. Here, we determined the crystal structures of SERCA2b and its C-terminal splicing variant SERCA2a, both in the E1-2Ca-adenylyl methylenediphosphonate (AMPPCP) state.

Remote Coupled Drastic β-Barrel to β-Sheet Transition of the Protein Translocation Motor.

The membrane protein SecDF, belonging to the RND superfamily, enhances protein translocation at the extracytoplasmic side using a proton gradient. Here, we report the crystal structure of SecDF in a form we named Super-membrane-facing (Super F) form, demonstrating a β-barrel architecture instead of the previously reported β-sheet structure. Through this structural insight and supporting results of an in vivo crosslinking experiment, we propose a remote coupling model in which a structural change of the transmembrane region drives a functional, extracytoplasmic conformational transition.

Tunnel Formation Inferred from the I-Form Structures of the Proton-Driven Protein Secretion Motor SecDF.

Protein secretion mediated by SecYEG translocon and SecA ATPase is enhanced by membrane-embedded SecDF by using proton motive force. A previous structural study of SecDF indicated that it comprises 12 transmembrane helices that can conduct protons and three periplasmic domains, which form at least two characterized transition states, termed the F and I forms. We report the structures of full-length SecDF in I form at 2.