Structural basis of Epstein-Barr virus gp350 receptor recognition and neutralization.

Epstein-Barr virus (EBV) is an oncogenic virus associated with multiple lymphoid malignancies and autoimmune diseases. During infection in B cells, EBV uses its major glycoprotein gp350 to recognize the host receptor CR2, initiating viral attachment, a process that has lacked direct structural evidence for decades. In this study, we resolved the structure of the gp350-CR2 complex, elucidated their key interactions, and determined the site-specific N-glycosylation map of gp350.

Single-molecule two- and three-colour FRET studies reveal a transition state in SNARE disassembly by NSF.

SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins are the minimal machinery required for vesicle fusion in eukaryotes. Formation of a highly stable four-helix bundle consisting of SNARE motif of these proteins, drives vesicle/membrane fusion involved in several physiological processes such as neurotransmission. Recycling/disassembly of the protein machinery involved in membrane fusion is essential and is facilitated by an AAA+ ATPase, N-ethylmaleimide sensitive factor (NSF) in the presence of an adapter protein, α-SNAP.

Defects in Exosome Biogenesis Are Associated with Sensorimotor Defects in Zebrafish Mutants.

Mutations in human are associated with neurodevelopmental defects, including motor delays and defective muscle tone. encodes a AAA-ATPase required for membrane scission, but how mutations in lead to impaired control of motor function is not known. Here we identified a mutation in zebrafish , T248I, that affects sensorimotor transformation.

Structural insight into synergistic activation of human 3-methylcrotonyl-CoA carboxylase.

The enzymes 3-methylcrotonyl-coenzyme A (CoA) carboxylase (MCC), pyruvate carboxylase and propionyl-CoA carboxylase belong to the biotin-dependent carboxylase family located in mitochondria. They participate in various metabolic pathways in human such as amino acid metabolism and tricarboxylic acid cycle. Many human diseases are caused by mutations in those enzymes but their structures have not been fully resolved so far.

In situ structural determination of cyanobacterial phycobilisome-PSII supercomplex by STAgSPA strategy.

Photosynthesis converting solar energy to chemical energy is one of the most important chemical reactions on earth. In cyanobacteria, light energy is captured by antenna system phycobilisomes (PBSs) and transferred to photosynthetic reaction centers of photosystem II (PSII) and photosystem I (PSI). While most of the protein complexes involved in photosynthesis have been characterized by in vitro structural analyses, how these protein complexes function together in vivo is not well understood.

Activity-based metaproteomics driven discovery and enzymological characterization of potential α-galactosidases in the mouse gut microbiome.

The gut microbiota offers an extensive resource of enzymes, but many remain uncharacterized. To distinguish the activities of similar annotated proteins and mine the potentially applicable ones in the microbiome, we applied an effective Activity-Based Metaproteomics (ABMP) strategy using a specific activity-based probe (ABP) to screen the entire gut microbiome for directly discovering active enzymes and their potential applications, not for exploring host-microbiome interactions. By using an activity-based cyclophellitol aziridine probe specific to α-galactosidases (AGAL), we successfully identified and characterized several gut microbiota enzymes possessing AGAL activities.

Structure of the intact Tom20 receptor in the human translocase of the outer membrane complex.

The translocase of the outer membrane (TOM) complex serves as the main gate for preproteins entering mitochondria and thus plays a pivotal role in sustaining mitochondrial stability. Precursor proteins, featuring amino-terminal targeting signals (presequences) or internal targeting signals, are recognized by the TOM complex receptors Tom20, Tom22, and Tom70, and then translocated into mitochondria through Tom40. By using chemical cross-linking to stabilize Tom20 in the TOM complex, this study unveils the structure of the human TOM holo complex, encompassing the intact Tom20 component, at a resolution of approximately 6 Å by cryo-electron microscopy.

Structure of the red-shifted Fittonia albivenis photosystem I.

Photosystem I (PSI) from Fittonia albivenis, an Acanthaceae ornamental plant, is notable among green plants for its red-shifted emission spectrum. Here, we solved the structure of a PSI-light harvesting complex I (LHCI) supercomplex from F. albivenis at 2.

Ultrastructural insights into cellular organization, energy storage and ribosomal dynamics of an ammonia-oxidizing archaeon from oligotrophic oceans.

Introduction: Nitrososphaeria, formerly known as , constitute a diverse and widespread group of ammonia-oxidizing archaea (AOA) inhabiting ubiquitously in marine and terrestrial environments, playing a pivotal role in global nitrogen cycling. Despite their importance in Earth's ecosystems, the cellular organization of AOA remains largely unexplored, leading to a significant unanswered question of how the machinery of these organisms underpins metabolic functions.

Methods: In this study, we combined spherical-chromatic-aberration-corrected cryo-electron tomography (cryo-ET), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS) to unveil the cellular organization and elemental composition of SCM1, a representative member of marine .

The structural basis for light acclimation in phycobilisome light harvesting systems systems in Porphyridium purpureum.

Photosynthetic organisms adapt to changing light conditions by manipulating their light harvesting complexes. Biophysical, biochemical, physiological and genetic aspects of these processes are studied extensively. The structural basis for these studies is lacking.

Regulatory dynamics of the higher-plant PSI-LHCI supercomplex during state transitions.

State transition is a fundamental light acclimation mechanism of photosynthetic organisms in response to the environmental light conditions. This process rebalances the excitation energy between photosystem I (PSI) and photosystem II through regulated reversible binding of the light-harvesting complex II (LHCII) to PSI. However, the structural reorganization of PSI-LHCI, the dynamic binding of LHCII, and the regulatory mechanisms underlying state transitions are less understood in higher plants.

Brain structure and structural basis of neurodegenerative diseases.

The brain is one of the most complex organs in nature. In this organ, multiple neurons, neuron clusters, or multiple brain regions are interconnected to form a complex structural network where various brain functions are completed through interaction. In recent years, multiple tools and techniques have been developed to analyze the composition of different cell types in the brain and to construct the brain atlas on macroscopic, mesoscopic, and microscopic levels.

Nuclear export of pre-60S particles through the nuclear pore complex.

The nuclear pore complex (NPC) is the bidirectional gate that mediates the exchange of macromolecules or their assemblies between nucleus and cytoplasm. The assembly intermediates of the ribosomal subunits, pre-60S and pre-40S particles, are among the largest cargoes of the NPC and the export of these gigantic ribonucleoproteins requires numerous export factors. Here we report the cryo-electron microscopy structure of native pre-60S particles trapped in the channel of yeast NPCs.

Structural insights into assembly of TRAPPII and its activation of Rab11/Ypt32.

Transport protein particle (TRAPP) complexes belong to the multisubunit tethering complex. They are guanine nucleotide exchange factors (GEFs) that play essential roles in secretory and endocytic recycling pathway and autophagy. There are two major forms of TRAPP complexes, TRAPPII and TRAPPIII, which share a core set of small subunits.

Determining protein structures in cellular lamella at pseudo-atomic resolution by GisSPA.

Cryo-electron tomography is a major tool used to study the structure of protein complexes in situ. However, the throughput of tilt-series image data collection is still quite low. Here, we show that GisSPA, a GPU accelerated program, can translationally and rotationally localize the target protein complex in cellular lamellae, as prepared with a focused ion beam, using single cryo-electron microscopy images without tilt-series, and reconstruct the protein complex at near-atomic resolution.

Structure of the Acidobacteria homodimeric reaction center bound with cytochrome c.

Photosynthesis converts light energy to chemical energy to fuel life on earth. Light energy is harvested by antenna pigments and transferred to reaction centers (RCs) to drive the electron transfer (ET) reactions. Here, we present cryo-electron microscopy (cryo-EM) structures of two forms of the RC from the microaerophilic Chloracidobacterium thermophilum (CabRC): one containing 10 subunits, including two different cytochromes; and the other possessing two additional subunits, PscB and PscZ.

Structural insights into PA3488-mediated inactivation of Pseudomonas aeruginosa PldA.

PldA, a phospholipase D (PLD) effector, catalyzes hydrolysis of the phosphodiester bonds of glycerophospholipids-the main component of cell membranes-and assists the invasion of the opportunistic pathogen Pseudomonas aeruginosa. As a cognate immunity protein, PA3488 can inhibit the activity of PldA to avoid self-toxicity. However, the precise inhibitory mechanism remains elusive.

Structural basis of Tom20 and Tom22 cytosolic domains as the human TOM complex receptors.

Mitochondrial preproteins synthesized in cytosol are imported into mitochondria by a multisubunit translocase of the outer membrane (TOM) complex. Functioned as the receptor, the TOM complex components, Tom 20, Tom22, and Tom70, recognize the presequence and further guide the protein translocation. Their deficiency has been linked with neurodegenerative diseases and cardiac pathology.

Near-atomic structure of the inner ring of the Saccharomyces cerevisiae nuclear pore complex.

Nuclear pore complexes (NPCs) mediate bidirectional nucleocytoplasmic transport of substances in eukaryotic cells. However, the accurate molecular arrangement of NPCs remains enigmatic owing to their huge size and highly dynamic nature. Here we determined the structure of the asymmetric unit of the inner ring (IR monomer) at 3.

Structural basis for assembly of TRAPPII complex and specific activation of GTPase Ypt31/32.

Transport protein particle (TRAPP) complexes belong to the multiprotein tethering complex and exist in three forms-core TRAPP/TRAPPI, TRAPPII, and TRAPPIII. TRAPPII activates GTPase Ypt31/Ypt32 as the guanine nucleotide exchange factor in the trans-Golgi network to determine the maturation of Golgi cisternae into post-Golgi carriers in yeast. Here, we present cryo-EM structures of yeast TRAPPII in apo and Ypt32-bound states.

In situ cryo-ET structure of phycobilisome-photosystem II supercomplex from red alga.

Phycobilisome (PBS) is the main light-harvesting antenna in cyanobacteria and red algae. How PBS transfers the light energy to photosystem II (PSII) remains to be elucidated. Here we report the in situ structure of the PBS-PSII supercomplex from UTEX 2757 using cryo-electron tomography and subtomogram averaging.

Structural insights into the mechanism of human NPC1L1-mediated cholesterol uptake.

Niemann-Pick C1-like 1 (NPC1L1) protein plays a central role in the intestinal cholesterol absorption and is the target of a drug, ezetimibe, which inhibits NPC1L1 to reduce cholesterol absorption. Here, we present cryo-electron microscopy structures of human NPC1L1 in apo state, cholesterol-enriched state, and ezetimibe-bound state to reveal molecular details of NPC1L1-mediated cholesterol uptake and ezetimibe inhibition. Comparison of these structures reveals that the sterol-sensing domain (SSD) could respond to the cholesterol level alteration by binding different number of cholesterol molecules.

Structural insights into cyanobacterial photosystem II intermediates associated with Psb28 and Tsl0063.

Photosystem II (PSII) is a multisubunit pigment-protein complex and catalyses light-induced water oxidation, leading to the conversion of light energy into chemical energy and the release of dioxygen. We analysed the structures of two Psb28-bound PSII intermediates, Psb28-RC47 and Psb28-PSII, purified from a psbV-deletion strain of the thermophilic cyanobacterium Thermosynechococcus vulcanus, using cryo-electron microscopy. Both Psb28-RC47 and Psb28-PSII bind one Psb28, one Tsl0063 and an unknown subunit.