Light-harvesting complexes (LHCs) are diversified among photosynthetic organisms, and the structure of photosystem I-LHC (PSI-LHCI) supercomplex has been shown to be variable depending on species organisms. However, structural evolutionary correlations red-lineage LHCs unknown. Here, we determined a 1.92-Å resolution cryoelectron microscopic PSI-LHCI isolated from red alga Cyanidium caldarium RK-1 (NIES-2137), which is an important taxon in Cyanidiophyceae. We subsequently investigated...

Abstract Acaryochloris marina is one of the cyanobacterial species that can use far-red light to drive photochemical reactions for oxygenic photosynthesis. Here, we report structure A. photosystem I (PSI) reaction center, determined by cryo-electron microscopy at 2.58 Å resolution. The reveals an arrangement electron carriers and light-harvesting pigments distinct from other type centers. paired chlorophyll, or special pair (also referred as P740 in this case), a dimer chlorophyll d its...

Photosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure some intermediate structures. However, these structures are the crystalline state final not been solved. Here we analyzed of PSII solution at 1.95 Å resolution by single-particle cryo-electron microscopy (cryo-EM). The obtained is similar to crystal structure, but PsbY subunit was visible cryo-EM indicating that it represents physiological more closely....

Structure analysis of small crystals is important in areas ranging from synthetic organic chemistry to pharmaceutical and material sciences, as many compounds do not yield large crystals. Here we present the detailed characterization structure an molecule, rhodamine-6G, determined at a resolution 0.82 Å by X-ray free-electron laser (XFEL). Direct comparison this with that obtained electron crystallography same sample batch microcrystals shows both methods can accurately distinguish position...

Rotary ATPases, including F 1 O -, V and A -ATPases, are molecular motors that exhibit rotational movements for energy conversion. In the gliding bacterium, Mycoplasma mobile , a dimeric -like ATPase forms chain structure within cell, which is proposed to drive motility. However, mechanisms of force generation transmission remain unclear. We determined electron cryomicroscopy (cryo-EM) complex. The revealed an assembly distinct from those -ATPases. unit associated by two subunits GliD GliE...

A new cryo-EM system has been investigated for single particle analysis of protein structures. The provides parallel illumination a highly-coherent 300 kV electron beam from cold-field emission gun, and boosts image contrast with an in-column energy filter hole-free phase plate. It includes motorized cryo-sample loading automated liquid-nitrogen filling cooling multiple samples. In this study, we describe gun characteristics, demonstrate the suitability reconstructions. performance is tested...

Photosystem I (PSI) is a multi-subunit pigment-protein complex that functions in light-harvesting and photochemical charge-separation reactions, followed by reduction of NADP to NADPH required for CO 2 fixation photosynthetic organisms. PSI from different organisms has variety chlorophylls (Chls), some which are at lower-energy levels than its reaction center P700, special pair Chls, called low-energy Chls. However, the sites Chls still under debate. Here, we solved 2.04-Å resolution...

Abstract Cyanobacteria, glaucophytes, and rhodophytes utilize giant, light-harvesting phycobilisomes (PBSs) for capturing solar energy conveying it to photosynthetic reaction centers. PBSs are compositionally structurally diverse, exceedingly complex, all of which pose a challenge comprehensive understanding their function. To date, three detailed architectures by cryo-electron microscopy (cryo-EM) have been described: hemiellipsoidal type, block-type from rhodophytes, cyanobacterial...

Abstract Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions. The cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, their binding property and functional roles PSI still missing. We analyzed a cryo-electron microscopy structure of PSI-IsiA supercomplex isolated from grown an condition. contains six IsiA subunits associated with the PsaA side core monomer. Three were identified as IsiA1 IsiA2. lacks PsaL subunit; instead,...

Abstract Hydrogen bonding, bond polarity, and charges in protein molecules play critical roles the stabilization of structures, as well affecting their functions such enzymatic catalysis, electron transfer, ligand binding. These effects can potentially be measured Coulomb potentials using cryogenic microscopy (cryo-EM). We here present properties hydrogen a sub-1.2 Å resolution structure complex, apoferritin, by single-particle cryo-EM. A weighted difference map reveals positive densities...

Mycoplasma pneumoniae forms a membrane protrusion at cell pole and is known to adhere solid surfaces, including animal cells, can glide on these surfaces with speed up 1 μm per second. Notably, gliding appears be involved in the infectious process addition providing bacteria means of escaping host's immune systems. However, genome M. does not encode any genes found other bacterial motility systems or conventional motor proteins that are responsible for eukaryotic motility. Thus, further...

In cryo-electron microscopy (cryo-EM) data collection, locating a target object is error-prone. Here, we present machine learning-based approach with real-time locator named yoneoLocr using YOLO, well-known detection system. Implementation shows its effectiveness in rapidly and precisely carbon holes single particle cryo-EM crystals evaluating electron diffraction (ED) patterns automated crystallography (cryo-EX) collection. The proposed will advance high-throughput accurate collection of...

Abstract Enantioselectivity of helical aggregation is conventionally directed either by its homochiral ingredients or introduction chiral catalysis. The fundamental question, then, whether that consists only achiral components can obtain enantioselectivity in the absence Here, exploiting enantiospecific interaction due to chiral-induced spin selectivity (CISS) has been known work enantio-separate a racemic mixture molecules, we demonstrate assembly mesoscale supramolecules consisting cobalt...

Mycoplasma mobile, a fish pathogen, exhibits gliding motility using ATP hydrolysis on solid surfaces, including animal cells. The machinery can be divided into surface and internal structures. structure of the motor is composed 28 so-called "chains" that are each 17 repeating protein units called "particles." These proteins include homologs catalytic α β subunits F1-ATPase. In this study, we isolated particles determined their structures negative-staining electron microscopy high-speed...

A theoretical model of the far-red-light-adapted photosystem I (PSI) reaction center (RC) complex a cyanobacterium, Acaryochloris marina (AmPSI), was constructed based on exciton theory and recently identified molecular structure AmPSI by Hamaguchi et al. (Nat. Commun., 2021, 12, 2333). A. performs photosynthesis under visible to far-red light (400-750 nm), which is absorbed chlorophyll d (Chl-d). It in contrast situation all other oxygenic photosynthetic processes cyanobacteria plants,...

ABSTRACT The binding and gliding of Mycoplasma mobile on a plastic plate covered by 53 uniform oligosaccharides were analyzed. Mycoplasmas bound to glided only 21 the fixed sialylated (SOs), showing that sialic acid is essential as target. affinities mostly consistent with our previous results inhibitory effects free SOs suggested M. recognizes from nonreducing end four continuous sites follows. (i ii) A at tightly recognized tandemly connected two sites. (iii) third site loose groove may be...

Abstract Endothelin type B receptor (ET R) plays a crucial role in regulating blood pressure and humoral homeostasis, making it an important therapeutic target for related diseases. ET R activation by the endogenous peptide hormones endothelin (ET)−1–3 stimulates several signaling pathways, including G s , i/o q/11 12/13 β-arrestin. Although conserved NPxxY motif transmembrane helix 7 (TM7) is during GPCR activation, possesses lesser known NPxxL motif. In this study, we present cryo-EM...

Mycoplasma pneumoniae is a human pathogen that glides on host cell surfaces by repeated catch and release mechanism using sialylated oligosaccharides. At pole, this organism forms protrusion called an attachment organelle composed of surface structures, including adhesin complex internal core structure. To clarify the structure function organelle, we focused component, P65, which essential for stabilization adjacent proteins P30 HMW2, respectively. Analysis its amino acid sequence (405...

Mycoplasma pneumoniae is a human pathogen that glides on host cell surfaces by repeated catch and release mechanism using sialylated oligosaccharides. At pole, this organism forms protrusion called an attachment organelle composed of surface structures, including adhesin complex internal core structure. To clarify the structure function organelle, we focused component, P65, which essential for stabilization adjacent proteins P30 HMW2, respectively. Analysis its amino acid sequence (405...

Nanoparticle capsules (NCs), capsule-like structures composed of inorganic nanoparticles (NPs), hold great potential for diverse applications due to their structure-driven functionality and the unique properties NPs. Despite advancements in NC formation methods, achieving both stable efficient material encapsulation remains challenging. In this study, a simple versatile method is developed NCs. Inorganic NCs are formed from oligo(ethylene glycol) (OEG)-modified NPs via self-assembly at...

Sialic acids, terminal structures of sialylated glycoconjugates, are widely distributed in animal tissues and often involved intercellular recognitions, including some bacteria viruses. Mycoplasma mobile, a fish pathogenic bacterium, binds to sialyloligosaccharide (SO) through adhesin Gli349 glides on host cell surfaces. The amino acid sequence shows no similarity known SO-binding proteins. In the present study, we predicted binding part Gli349, produced it Escherichia coli proved its...

Abstract We have designed and evaluated a cryo-electron microscopy (cryo-EM) system for higher-resolution single particle analysis high-precision electron 3D crystallography. The comprises JEOL CRYO ARM 300 microscope—the first machine of this model—and direct detection device camera, scintillator-coupled GPU clusters connected with camera control computer software automated-data collection efficient accurate operation. microscope provides parallel illumination highly coherent 300-kV beam to...

Endo-β-N-acetylglucosaminidases are thought to be key enzymes in the catabolism of asparagine-linked oligosaccharides. However, little is known about this type basidiomycetes. We investigated endo-β-N-acetylglucosaminidases basidiomycetes using fluorescence-labeled glycoasparagines as substrates. Flammulina velutipes showed high activity and its enzyme was named endo-β-N-acetylglucosaminidase FV (Endo FV). The purified from fruiting bodies F. separated into two forms. Endo specific for...