Inspired by the orderly stacked nanostructure and highly integrated function of thylakoids in a natural photosynthesis system, multishell g-CN (MSCN) nanocapsule photocatalysts have been prepared by SiO hard template with different shell layers. The resultant triple-shell g-CN (TSCN) nanocapsules display superior photocatalysis performance to single-shell and double-shell counterparts owing to excellent visible-light harvesting and electron transfer properties. Specially, with the increase of the shell layer number, light harvesting is greatly enhanced. There is an increase of the entire visible range absorption arising from the multiple scattering and reflection of the incident light within multishell nanoarchitectures as well as the light transmission within the porous thin shells, and an increase of absorption edge arising from the decreased quantum size effect. The electron transfer is greatly accelerated by the mesopores in the thin shells as nanoconduits and the high specific surface area of TSCN (310.7 m g). With the tailored hierarchical nanostructure features, TSCN exhibits a superior visible-light H-generation activity of 630 μmol h g (λ > 420 nm), which is among one of the most efficient metal-free g-CN photocatalysts. This study demonstrates a bioinspired approach to the rational design of high-performance nanostructured visible-light photocatalysts.

Recent findings have revealed that the protein gasdermin D (GSDMD) plays key roles in cell pyroptosis. GSDMD binds lipids and forms pore structures to induce pyroptosis upon microbial infection and associated danger signals. However, detailed structural information for GSDMD remains unknown. Here, we report the crystal structure of the C-terminal domain of human GSDMD (GSDMD-C) at 2.64-Å resolution. The first loop on GSDMD-C inserts into the N-terminal domain (GSDMD-N), which helps stabilize the conformation of the full-length GSDMD. Substitution of this region by a short linker sequence increased levels of cell death. Mutants F283A and F283R can increase protein heterogeneity in vitro and are capable of undergoing cell pyroptosis in 293T cells. The small-angle X-ray-scattering envelope of human GSDMD is consistent with the modeled GSDMD structure and mouse GSDMA3 structure, which suggests that GSDMD adopts an autoinhibited conformation in solution. The positive potential surface of GSDMD-N covered by GSDMD-C is exposed after being released from the autoinhibition state and can form high-order oligomers via a charge-charge interaction. Furthermore, by mapping different regions of GSDMD, we determined that one short segment is sufficient to kill bacteria in vitro and can efficiently inhibit cell growth in and These findings reveal that GSDMD-C acts as an auto-inhibition executor and GSDMD-N could form pore structures via a charge-charge interaction upon cleavage by caspases during cell pyroptosis.

SUMMARY In the Drosophila immune response, bacterial derived diaminopimelic acid-type peptidoglycan binds the receptors PGRP-LC and PGRP-LE, which through interaction with the adaptor protein Imd leads to activation of the NF-κB homolog Relish and robust antimicrobial peptide gene expression. PGRP-LC, PGRP-LE, and Imd each contain a motif with some resemblance to the RIP Homotypic Interaction Motif (RHIM), a domain found in mammalian RIPK proteins forming functional amyloids during necroptosis. Here we found that despite sequence divergence, these Drosophila cryptic RHIMs formed amyloid fibrils in vitro and in cells. Amyloid formation was required for signaling downstream of Imd, and in contrast to the mammalian RHIMs, was not associated with cell death. Furthermore, amyloid formation constituted a regulatable step and could be inhibited by Pirk, an endogenous feedback regulator of this pathway. Thus, diverse sequence motifs are capable of forming amyloidal signaling platforms, and the formation of these platforms may present a regulatory point in multiple biological processes.

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