A cardioviral 2C-ATP complex structure reveals the essential role of a conserved arginine in regulation of cardioviral 2C activity.

Unlabelled: 2C is a highly conserved picornaviral non-structural protein with ATPase activity and plays a multifunctional role in the viral life cycle as a promising target for anti-picornavirus drug development. While the structure-function of enteroviral 2Cs have been well studied, cardioviral 2Cs remain largely uncharacterized. Here, an endogenous ATP molecule was identified in the crystal structure of 2C from encephalomyocarditis virus (EMCV, Cardiovirus A).

A conductive catecholate-based framework coordinated with unsaturated bismuth boosts CO electroreduction to formate.

Bismuth-based metal-organic frameworks (Bi-MOFs) have received attention in electrochemical CO-to-formate conversion. However, the low conductivity and saturated coordination of Bi-MOFs usually lead to poor performance, which severely limits their widespread application. Herein, a conductive catecholate-based framework with Bi-enriched sites (HHTP, 2,3,6,7,10,11-hexahydroxytriphenylene) is constructed and the zigzagging corrugated topology of Bi-HHTP is first unraveled single-crystal X-ray diffraction.

Allosteric regulation of Senecavirus A 3Cpro proteolytic activity by an endogenous phospholipid.

Seneca virus A (SVA) is an emerging novel picornavirus that has recently been identified as the causative agent of many cases of porcine vesicular diseases in multiple countries. In addition to cleavage of viral polyprotein, the viral 3C protease (3Cpro) plays an important role in the regulation of several physiological processes involved in cellular antiviral responses by cleaving critical cellular proteins. Through a combination of crystallography, untargeted lipidomics, and immunoblotting, we identified the association of SVA 3Cpro with an endogenous phospholipid molecule, which binds to a unique region neighboring the proteolytic site of SVA 3Cpro.

Exploring AlphaFold2's Performance on Predicting Amino Acid Side-Chain Conformations and Its Utility in Crystal Structure Determination of B318L Protein.

Recent technological breakthroughs in machine-learning-based AlphaFold2 (AF2) are pushing the prediction accuracy of protein structures to an unprecedented level that is on par with experimental structural quality. Despite its outstanding structural modeling capability, further experimental validations and performance assessments of AF2 predictions are still required, thus necessitating the development of integrative structural biology in synergy with both computational and experimental methods. Focusing on the B318L protein that plays an essential role in the African swine fever virus (ASFV) for viral replication, we experimentally demonstrate the high quality of the AF2 predicted model and its practical utility in crystal structural determination.

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.

Cu-Based Organic-Inorganic Composite Materials for Electrochemical CO Reduction.

Electrochemical CO reduction reaction (CO RR) is an attractive pathway to convert CO into value-added chemicals and fuels. Copper (Cu) is the most effective monometallic catalyst for converting CO into multi-carbon products, but suffers from high overpotentials and poor selectivity. Therefore, it is essential to design efficient Cu-based catalyst to improve the selectivity of specific products.

Insights into the Neutralization and DNA Binding of Toxin-Antitoxin System ParE-CopA by Structure-Function Studies.

ParE-CopA is a new type II toxin-antitoxin (TA) system in prophage CP4So that plays an essential role in circular CP4So maintenance after the excision in . The toxin ParE severely inhibits cell growth, while CopA functions as an antitoxin to neutralize ParE toxicity through direct interactions. However, the molecular mechanism of the neutralization and autoregulation of the TA operon transcription remains elusive.

NUDIM: A non-uniform fast Fourier transform based dual-space constraint iterative reconstruction method in biological electron tomography.

Electron tomography, a powerful imaging tool for studying 3D structures of macromolecular assemblies, always suffers from imperfect reconstruction with limited resolution due to the intrinsic low signal-to-noise ratio (SNR) and inaccessibility to certain tilt angles induced by radiation damage or mechanical limitation. In order to compensate for such insufficient data with low SNR and further improve imaging resolution, prior knowledge constraints about the objects in both real space and reciprocal space are thus exploited during tomographic reconstruction. However, direct Fast Fourier transform (FFT) between real space and reciprocal space remains extraordinarily challenging owing to their inconsistent grid sampling modes, e.

Structure and Biochemical Characteristic of the Methyltransferase (MTase) Domain of RNA Capping Enzyme from African Swine Fever Virus.

African swine fever virus (ASFV) is a complex nucleocytoplasmic large DNA virus (NCLDV) that causes a devastating swine disease and it is urgently needed to develop effective anti-ASFV vaccines and drugs. The process of mRNA 5'-end capping is a common characteristic in eukaryotes and many viruses, and the cap structure is required for mRNA stability and efficient translation. The ASFV protein pNP868R was found to have guanylyltransferase (GTase) activity involved in mRNA capping.

Structural and functional characterization of the deep-sea thermophilic bacteriophage GVE2 tailspike protein.

The genome of the thermophilic bacteriophage GVE2 encodes a putative tailspike protein (GVE2 TSP). Here we report the crystal structure of the truncated GVE2 TSP at 2.0-Å resolution lacking 204 amino acid residues at its N-terminus (ΔnGVE2 TSP), possessing a "vase" outline similar to other TSP's structures.

Characterization of the Pseudomonas aeruginosa T6SS PldB immunity proteins PA5086, PA5087 and PA5088 explains a novel stockpiling mechanism.

The bacterial type VI secretion system (T6SS) secretes many toxic effectors to gain advantage in interbacterial competition and for eukaryotic host infection. The cognate immunity proteins of these effectors protect bacteria from their own effectors. PldB is a T6SS trans-kingdom effector in Pseudomonas aeruginosa that can infect both prokaryotic and eukaryotic cells.

Crystal structure of the nucleoid-associated protein Fis (PA4853) from Pseudomonas aeruginosa.

Factor for inversion stimulation (Fis) is a versatile bacterial nucleoid-associated protein that can directly bind and bend DNA to influence DNA topology. It also plays crucial roles in regulating bacterial virulence factors and in optimizing bacterial adaptation to various environments. Fis from Pseudomonas aeruginosa (PA4853, referred to as PaFis) has recently been found to be required for virulence by regulating the expression of type III secretion system (T3SS) genes.

Structural Insights Into the Transcriptional Regulation of HigBA Toxin-Antitoxin System by Antitoxin HigA in .

HigB-HigA is a bacterial toxin-antitoxin (TA) system in which the antitoxin HigA can mask the endoribonuclease activity of toxin HigB and repress the transcription of the TA operon by binding to its own promoter region. The opportunistic pathogen HigBA (PaHigBA) is closely associated with the pathogenicity by reducing the production of multiple virulence factors and biofilm formation. However, the molecular mechanism underlying HigBA TA operon transcription by PaHigA remains elusive.

An enzyme-free immunosensor for sensitive determination of procalcitonin using NiFe PBA nanocubes@TB as the sensing matrix.

In this work, a label-free electrochemical immunosensor was developed for the detection of procalcitonin (PCT), using toluidine blue functionalized NiFe Prussian-blue analog nanocubes (NiFe PBA nanocubes@TB) as a signal amplifier. NiFe PBA nanocubes was synthesized by a simple and efficient self-templating method in this work. NiFe PBA nanocubes with open-framework construction not only provides a larger specific area to load a mass of antibodies but produces an excellent signal without adding extra reaction reagent.

Conformational changes of antitoxin HigA from Escherichia coli str. K-12 upon binding of its cognate toxin HigB reveal a new regulation mechanism in toxin-antitoxin systems.

HigA functions as the antitoxin in HigB-HigA toxin-antitoxin system. It neutralizes HigB-mediated toxicity by forming a stable toxin-antitoxin complex. Here the crystal structure of isolated HigA from Escherichia coli str.

AuCu O-Embedded Mesoporous CeO Nanocomposites as a Signal Probe for Electrochemical Sensitive Detection of Amyloid-Beta Protein.

A sandwich-type electrochemical immunosensor for detecting amyloid-beta protein was fabricated based on Au NP-functionalized reduced graphene oxide (Au@rGO) as an effective sensing platform and AuCu O-embedded mesoporous CeO (AuCu O@m-CeO) nanocomposites as the catalytic matrix. The AuCu O@m-CeO composites were obtained by adjusting the amount of m-CeO in the reaction to expose enormous active sites. Also, AuCu O@m-CeO was applied as a matrix to immobilize antibodies by forming bridged bonds between m-CeO and carboxyl functional groups of antibodies without additional agents.

Crystal structure of the type VI immunity protein Tdi1 (Atu4351) from Agrobacterium tumefaciens.

The type VI secretion system (T6SS) is a novel multiprotein needle-like apparatus that is distributed widely in Gram-negative bacteria. Bacteria harboring T6SSs inject various effectors into both eukaryotic and prokaryotic cells for interspecies competition or virulence-related processes. The toxicities of the effectors can be neutralized by their cognate immunity proteins.

Facile Synthesis of CuO@TiO-PtCu Nanocomposites as a Signal Amplification Strategy for the Insulin Detection.

Novel ultrasensitive sandwich-type electrochemical immunosensor was proposed for the quantitative detection of insulin, a representative biomarker for diabetes. To this end, molybdenum disulfide nanosheet-loaded gold nanoparticles (MoS/Au NPs) were used as substrates to modify bare glassy carbon electrodes. MoS/Au NPs not only present superior biocompatible and large specific surface area to enhance the loading capacity of primary antibody (Ab) but also present good electrical conductivity to accelerate electron transfer rate.

Label-free electrochemical immunosensor for insulin detection by high-efficiency synergy strategy of Pd NPs@3D MoS towards HO.

Here, a novel HO-based electrochemical immunosensor utilizing Pd nanoparticles functionalized three-dimensional wrinkly amorphous MoS composites (Pd NPs@3D MoS) as the platform was developed for the determination of insulin. In this work, Pd NPs@3D MoS prepared in the presence of CTAB possessed an excellent catalytic activity for the reduction of HO. Furthermore, Pd NPs@3D MoS with favorable biological compatibility can conjugate a great many antibodies to capture insulin.

Crystal structures of multicopper oxidase CueO G304K mutant: structural basis of the increased laccase activity.

The multicopper oxidase CueO is involved in copper homeostasis and copper (Cu) tolerance in Escherichia coli. The laccase activity of CueO G304K mutant is higher than wild-type CueO. To explain this increase in activity, we solved the crystal structure of G304K mutant at 1.

The crystal structure of KSHV ORF57 reveals dimeric active sites important for protein stability and function.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a γ-herpesvirus closely associated with Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman disease. Open reading frame 57 (ORF57), a viral early protein of KSHV promotes splicing, stability and translation of viral mRNA and is essential for viral lytic replication. Previous studies demonstrated that dimerization of ORF57 stabilizes the protein, which is critical for its function.

Structural and biochemical characterization of the yeast HD domain containing protein YGK1 reveals a metal-dependent nucleoside 5'-monophosphatase.

HD-domain is a conserved domain, with the signature of histidine and aspartic (HD) residues doublets. HD-domain proteins may possess nucleotidase and phosphodiesterase activities, and they play important roles in signaling and nucleotide metabolism. In yeast, HD-domain proteins with nucleotidase activity remained unexplored.

Enhanced peroxidase-like properties of Au@Pt DNs/NG/Cu and application of sandwich-type electrochemical immunosensor for highly sensitive detection of CEA.

Effective treatment of cancer depends upon the early detection of the tumor marker. Here, we report on the development of a new immunosensor for early detection of carcinoembryonic antigen (CEA). Cubic Au@Pt dendritic nanomaterials functionalized nitrogen-doped graphene loaded with copper ion (Au@Pt DNs/NG/Cu) with enhanced peroxidase-like properties was synthesized as labels to effectively capture and immobilize secondary anti-CEA.

Structure-function analyses reveal the molecular architecture and neutralization mechanism of a bacterial HEPN-MNT toxin-antitoxin system.

Toxin-antitoxin (TA) loci in bacteria are small genetic modules that regulate various cellular activities, including cell growth and death. The two-gene module encoding a HEPN (higher eukaryotes and prokaryotes nucleotide-binding) domain and a cognate MNT (minimal nucleotidyltransferase) domain have been predicted to represent a novel type II TA system prevalent in archaea and bacteria. However, the neutralization mechanism and cellular targets of the TA family remain unclear.

Sandwich-type electrochemical immunosensor based on Au@Ag supported on functionalized phenolic resin microporous carbon spheres for ultrasensitive analysis of α-fetoprotein.

Signal amplification is crucial for obtaining low detection limits in electrochemical immunosensor. In this work, we developed a novel signal amplification strategy using Au@Ag nanoparticles loaded by polydopamine functionalized phenolic resin microporous carbon spheres (Au@Ag/PDA-PR-MCS). Phenolic resin microporous carbon spheres (PR-MCS) possesses uniform size and a large surface area (1656.