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1.
Protein Sci ; 33(4): e4946, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38501481

RESUMEN

The two major challenges in synchrotron size-exclusion chromatography coupled in-line with small-angle x-ray scattering (SEC-SAXS) experiments are the overlapping peaks in the elution profile and the fouling of radiation-damaged materials on the walls of the sample cell. In recent years, many post-experimental analyses techniques have been developed and applied to extract scattering profiles from these problematic SEC-SAXS data. Here, we present three modes of data collection at the BioSAXS Beamline 4-2 of the Stanford Synchrotron Radiation Lightsource (SSRL BL4-2). The first mode, the High-Resolution mode, enables SEC-SAXS data collection with excellent sample separation and virtually no additional peak broadening from the UHPLC UV detector to the x-ray position by taking advantage of the low system dispersion of the UHPLC. The small bed volume of the analytical SEC column minimizes sample dilution in the column and facilitates data collection at higher sample concentrations with excellent sample economy equal to or even less than that of the conventional equilibrium SAXS method. Radiation damage problems during SEC-SAXS data collection are evaded by additional cleaning of the sample cell after buffer data collection and avoidance of unnecessary exposures through the use of the x-ray shutter control options, allowing sample data collection with a clean sample cell. Therefore, accurate background subtraction can be performed at a level equivalent to the conventional equilibrium SAXS method without requiring baseline correction, thereby leading to more reliable downstream structural analysis and quicker access to new science. The two other data collection modes, the High-Throughput mode and the Co-Flow mode, add agility to the planning and execution of experiments to efficiently achieve the user's scientific objectives at the SSRL BL4-2.


Asunto(s)
Sincrotrones , Difracción de Rayos X , Dispersión del Ángulo Pequeño , Cromatografía en Gel
2.
Proc Natl Acad Sci U S A ; 121(6): e2300644120, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38306481

RESUMEN

It is unclear how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to the strong but ineffective inflammatory response that characterizes severe Coronavirus disease 2019 (COVID-19), with amplified immune activation in diverse cell types, including cells without angiotensin-converting enzyme 2 receptors necessary for infection. Proteolytic degradation of SARS-CoV-2 virions is a milestone in host viral clearance, but the impact of remnant viral peptide fragments from high viral loads is not known. Here, we examine the inflammatory capacity of fragmented viral components from the perspective of supramolecular self-organization in the infected host environment. Interestingly, a machine learning analysis to SARS-CoV-2 proteome reveals sequence motifs that mimic host antimicrobial peptides (xenoAMPs), especially highly cationic human cathelicidin LL-37 capable of augmenting inflammation. Such xenoAMPs are strongly enriched in SARS-CoV-2 relative to low-pathogenicity coronaviruses. Moreover, xenoAMPs from SARS-CoV-2 but not low-pathogenicity homologs assemble double-stranded RNA (dsRNA) into nanocrystalline complexes with lattice constants commensurate with the steric size of Toll-like receptor (TLR)-3 and therefore capable of multivalent binding. Such complexes amplify cytokine secretion in diverse uninfected cell types in culture (epithelial cells, endothelial cells, keratinocytes, monocytes, and macrophages), similar to cathelicidin's role in rheumatoid arthritis and lupus. The induced transcriptome matches well with the global gene expression pattern in COVID-19, despite using <0.3% of the viral proteome. Delivery of these complexes to uninfected mice boosts plasma interleukin-6 and CXCL1 levels as observed in COVID-19 patients.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Animales , Ratones , Células Endoteliales , Proteoma , Péptidos
3.
Biophys J ; 122(12): 2456-2474, 2023 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-37147801

RESUMEN

The cell-cell adhesion cadherin-catenin complexes recruit vinculin to the adherens junction (AJ) to modulate the mechanical couplings between neighboring cells. However, it is unclear how vinculin influences the AJ structure and function. Here, we identified two patches of salt bridges that lock vinculin in the head-tail autoinhibited conformation and reconstituted the full-length vinculin activation mimetics bound to the cadherin-catenin complex. The cadherin-catenin-vinculin complex contains multiple disordered linkers and is highly dynamic, which poses a challenge for structural studies. We determined the ensemble conformation of this complex using small-angle x-ray and selective deuteration/contrast variation small-angle neutron scattering. In the complex, both α-catenin and vinculin adopt an ensemble of flexible conformations, but vinculin has fully open conformations with the vinculin head and actin-binding tail domains well separated from each other. F-actin binding experiments show that the cadherin-catenin-vinculin complex binds and bundles F-actin. However, when the vinculin actin-binding domain is removed from the complex, only a minor fraction of the complex binds to F-actin. The results show that the dynamic cadherin-catenin-vinculin complex employs vinculin as the primary F-actin binding mode to strengthen AJ-cytoskeleton interactions.


Asunto(s)
Actinas , Cadherinas , Cadherinas/metabolismo , Actinas/metabolismo , Vinculina/metabolismo , alfa Catenina/química , Unión Proteica , Citoesqueleto de Actina/metabolismo , Adhesión Celular
4.
J Biol Chem ; 299(6): 104765, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37121546

RESUMEN

Influenza hemagglutinin (HA) is a prototypical class 1 viral entry glycoprotein, responsible for mediating receptor binding and membrane fusion. Structures of its prefusion and postfusion forms, embodying the beginning and endpoints of the fusion pathway, have been extensively characterized. Studies probing HA dynamics during fusion have begun to identify intermediate states along the pathway, enhancing our understanding of how HA becomes activated and traverses its conformational pathway to complete fusion. HA is also the most variable, rapidly evolving part of influenza virus, and it is not known whether mechanisms of its activation and fusion are conserved across divergent viral subtypes. Here, we apply hydrogen-deuterium exchange mass spectrometry to compare fusion activation in two subtypes of HA, H1 and H3. Our data reveal subtype-specific behavior in the regions of HA that undergo structural rearrangement during fusion, including the fusion peptide and HA1/HA2 interface. In the presence of an antibody that inhibits the conformational change (FI6v3), we observe that acid-induced dynamic changes near the epitope are dampened, but the degree of protection at the fusion peptide is different for the two subtypes investigated. These results thus provide new insights into variation in the mechanisms of influenza HA's dynamic activation and its inhibition.


Asunto(s)
Glicoproteínas Hemaglutininas del Virus de la Influenza , Orthomyxoviridae , Humanos , Glicoproteínas Hemaglutininas del Virus de la Influenza/química , Hemaglutininas , Concentración de Iones de Hidrógeno , Gripe Humana , Orthomyxoviridae/metabolismo , Péptidos
5.
Microbiol Immunol ; 67(4): 185-193, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36628409

RESUMEN

Newcastle disease caused by highly pathogenic viruses of avian paramyxovirus serotype-1 (APMV-1) is a highly contagious poultry disease. Although a large-scale epidemic of Newcastle disease had occurred in Japan between the 1950s and the 2000s, there have been no outbreaks anywhere since 2010. In addition, there are no reports of epidemiological surveys of APMV-1 in wild birds in Japan in the last 10 years. We conducted the first epidemiological survey of APMV-1 in the Izumi plain, Kagoshima prefecture of southern Japan from the winter of 2018 to 2022. A total of 15 APMV-1 strains were isolated, and isolation rates from roosting water and duck fecal samples were 2.51% and 0.10%, respectively. These results indicate that the isolation method from environmental water may be useful for efficient surveillance of APMV-1 in wild birds. Furthermore, this is the first report on the success of APMV-1 isolation from environmental water samples. Genetic analysis of the Fusion (F) gene showed that all APMV-1 isolates were closely related to virus strains circulating among waterfowl in Far East Asian countries. All isolates have avirulent motifs in their cleavage site of F genes, all of which were presumed to be low pathogenic viruses in poultry. However, pathogenicity test using embryonated chicken eggs demonstrated that some isolates killed all chicken embryos regardless of viral doses inoculated (102 -106 50% egg infectious dose). These results indicated that APMV-1 strains, which are potentially pathogenic to chickens, are continuously brought into the Izumi plain by migrating wild birds.


Asunto(s)
Enfermedad de Newcastle , Virus de la Enfermedad de Newcastle , Embrión de Pollo , Animales , Virus de la Enfermedad de Newcastle/genética , Pollos , Japón/epidemiología , Serogrupo , Estaciones del Año , Filogenia , Animales Salvajes
6.
Acta Crystallogr D Struct Biol ; 78(Pt 11): 1315-1336, 2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36322416

RESUMEN

Through an expansive international effort that involved data collection on 12 small-angle X-ray scattering (SAXS) and four small-angle neutron scattering (SANS) instruments, 171 SAXS and 76 SANS measurements for five proteins (ribonuclease A, lysozyme, xylanase, urate oxidase and xylose isomerase) were acquired. From these data, the solvent-subtracted protein scattering profiles were shown to be reproducible, with the caveat that an additive constant adjustment was required to account for small errors in solvent subtraction. Further, the major features of the obtained consensus SAXS data over the q measurement range 0-1 Å-1 are consistent with theoretical prediction. The inherently lower statistical precision for SANS limited the reliably measured q-range to <0.5 Å-1, but within the limits of experimental uncertainties the major features of the consensus SANS data were also consistent with prediction for all five proteins measured in H2O and in D2O. Thus, a foundation set of consensus SAS profiles has been obtained for benchmarking scattering-profile prediction from atomic coordinates. Additionally, two sets of SAXS data measured at different facilities to q > 2.2 Å-1 showed good mutual agreement, affirming that this region has interpretable features for structural modelling. SAS measurements with inline size-exclusion chromatography (SEC) proved to be generally superior for eliminating sample heterogeneity, but with unavoidable sample dilution during column elution, while batch SAS data collected at higher concentrations and for longer times provided superior statistical precision. Careful merging of data measured using inline SEC and batch modes, or low- and high-concentration data from batch measurements, was successful in eliminating small amounts of aggregate or interparticle interference from the scattering while providing improved statistical precision overall for the benchmarking data set.


Asunto(s)
Benchmarking , Proteínas , Dispersión del Ángulo Pequeño , Difracción de Rayos X , Consenso , Reproducibilidad de los Resultados , Proteínas/química , Solventes
7.
Pathogens ; 11(9)2022 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-36145445

RESUMEN

The Izumi plain in the Kagoshima Prefecture, Japan, is known as an overwintering site for more than 30,000 migratory waterfowl, including endangered crane species. We previously reported that environmental water samples, from artificial wet paddies created as crane roost sites on the Izumi plain, are useful for avian influenza virus (AIV) surveillance. During the 2019/20 winter season, we collected 238 water samples from the crane roost sites and isolated 22 AIVs of six subtypes: one H1N1, one H3N2, seven H3N8, four H4N6, nine H6N6, and one H11N2 subtypes. Genetic analyses revealed that AIVs of the same subtype isolated from the Izumi plain during a single winter season exhibited multiple genetic constellations. Furthermore, phylogenetic analyses suggested that our H3N2 isolate may be a genetic reassortant between close relatives to our H3N8 and H11N2 isolates. Our study highlighted the importance of monitoring AIV circulation to better understand AIV ecology in migratory waterfowl populations.

8.
Transbound Emerg Dis ; 69(5): e2889-e2897, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35737749

RESUMEN

Environmental water-targeted surveillance of migratory aquatic birds at overwintering sites is potentially one of the most effective approaches for understanding the ecology of avian influenza viruses (AIVs). In this study, we improved the method for AIV isolation from environmental water samples by making a minor modification to our previously reported process. We experimentally demonstrated that the AIV recovery efficiency of the modified method was 10-100-fold higher than that of the original method. This improved isolation method allowed us to isolate a considerably larger number of AIV isolates from environmental water samples collected at an overwintering site for tens of thousands of migratory aquatic birds in Japan during the 2018/2019 winter season, compared with those during previous winter seasons. Genetic and phylogenetic analyses revealed that AIVs of the same subtypes with multiple genetic constellations were circulating in a single overwintering site during a single winter season. These findings indicate that our improved isolation method contributes to enhance environmental water-targeted surveillance and to a better understanding of AIV ecology in migratory aquatic bird populations by monitoring ongoing AIV circulation.


Asunto(s)
Virus de la Influenza A , Gripe Aviar , Animales , Animales Salvajes , Aves , Filogenia , Agua
9.
Transbound Emerg Dis ; 69(5): e2800-e2807, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35714126

RESUMEN

Crane-associated adenovirus 1 (CrAdV-1) is a proposed novel virus in the genus Aviadenovirus, first detected in faecal samples from hooded cranes (a vulnerable crane species) on the Izumi plain, a major overwintering site for migratory cranes in Japan. CrAdV-1 was genetically characterized in that study; however, its virological characteristics remain largely unclear. To investigate the prevalence and organ tropism of CrAdV-1, we collected swab and organ samples from dead or debilitated cranes on the Izumi plain. CrAdV-1 gene was detected in 47% (45/95) of tested cranes, comprising mainly hooded cranes but also white-naped and sandhill cranes. These results indicate that CrAdV-1 shedding is widespread among cranes overwintering on the Izumi plain. Phylogenetic analyses revealed that the 68 nucleotide sequences determined from the positive swabs formed a single cluster, suggesting phylogenetic differences between CrAdV-1 and other aviadenoviruses. CrAdV-1 prevalence showed a significant linear increase with time through the overwintering period (November to February), especially among juveniles. These findings indicate that CrAdV-1 spreads mainly by transmission between juveniles progressively through the overwintering period. The CrAdV-1 gene-positive rate was significantly higher in cloacal swabs than conjunctival or tracheal swabs. Copy numbers for the partial CrAdV-1 gene sequence were markedly high in the colon samples from three of the four cranes investigated for organ tropism. We also detected relatively high copy numbers in the cerebrum, trachea, lung and heart, suggesting that CrAdV-1 mainly targets these four organs and transmitted via the faecal-oral route and airborne transmission. These results contribute to further understanding of the virological characteristics of CrAdV-1.


Asunto(s)
Aviadenovirus , Aves , Animales , Japón/epidemiología , Filogenia , Prevalencia , Tropismo
11.
J Biol Chem ; 298(3): 101610, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35065072

RESUMEN

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic trait that can cause hemolytic anemia. To date, over 150 nonsynonymous mutations have been identified in G6PD, with pathogenic mutations clustering near the dimer and/or tetramer interface and the allosteric NADP+-binding site. Recently, our lab identified a small molecule that activates G6PD variants by stabilizing the allosteric NADP+ and dimer complex, suggesting therapeutics that target these regions may improve structural defects. Here, we elucidated the connection between allosteric NADP+ binding, oligomerization, and pathogenicity to determine whether oligomer stabilization can be used as a therapeutic strategy for G6PD deficiency (G6PDdef). We first solved the crystal structure for G6PDK403Q, a mutant that mimics the physiological acetylation of wild-type G6PD in erythrocytes and demonstrated that loss of allosteric NADP+ binding induces conformational changes in the dimer. These structural changes prevent tetramerization, are unique to Class I variants (the most severe form of G6PDdef), and cause the deactivation and destabilization of G6PD. We also introduced nonnative cysteines at the oligomer interfaces and found that the tetramer complex is more catalytically active and stable than the dimer. Furthermore, stabilizing the dimer and tetramer improved protein stability in clinical variants, regardless of clinical classification, with tetramerization also improving the activity of G6PDK403Q and Class I variants. These findings were validated using enzyme activity and thermostability assays, analytical size-exclusion chromatography (SEC), and SEC coupled with small-angle X-ray scattering (SEC-SAXS). Taken together, our findings suggest a potential therapeutic strategy for G6PDdef and provide a foundation for future drug discovery efforts.


Asunto(s)
Deficiencia de Glucosafosfato Deshidrogenasa , Glucosafosfato Deshidrogenasa , Glucosafosfato Deshidrogenasa/genética , Glucosafosfato Deshidrogenasa/metabolismo , Deficiencia de Glucosafosfato Deshidrogenasa/genética , Humanos , Mutación , NADP/metabolismo , Dispersión del Ángulo Pequeño , Difracción de Rayos X
12.
Arch Virol ; 166(6): 1547-1563, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33683475

RESUMEN

Virus maturation is found in all animal viruses and dsDNA bacteriophages that have been studied. It is a programmed process, cued by cellular environmental factors, that transitions a noninfectious, initial assembly product (provirus) to an infectious particle (virion). Nudaurelia capensis omega virus (NωV) is an ssRNA insect virus with T=4 quasi-symmetry. Over the last 20 years, NωV virus-like particles (VLPs) have been an attractive model for the detailed study of maturation. The novel feature of the system is the progressive transition from procapsid to capsid controlled by pH. Homogeneous populations of maturation intermediates can be readily produced at arbitrary intervals by adjusting the pH between 7.6 and 5.0. These intermediates were investigated using biochemical and biophysical methods to create a stop-frame transition series of this complex process. The studies reviewed here characterized the large-scale subunit reorganization during maturation (the particle changes size from 48 nm to 41 nm) as well as the mechanism of a maturation cleavage, a time-resolved study of cleavage site formation, and specific roles of quasi-equivalent subunits in the release of membrane lytic peptides required for cellular entry.


Asunto(s)
Virus ARN/fisiología , Proteínas Virales/metabolismo , Ensamble de Virus/fisiología , Animales , Virus ARN/genética , Proteínas Virales/genética
13.
Pathogens ; 10(2)2021 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-33557405

RESUMEN

We isolated two highly pathogenic avian influenza viruses (HPAIVs) of subtype H5N8 clade 2.3.4.4b from falcated duck (Anas falcata) feces and environmental water collected at an overwintering site in Japan. Our isolates were almost genetically identical to each other and showed high genetic similarity with H5N8 HPAIVs recently isolated in South Korea, a distant part of Japan, and European countries. These results suggest the potential role of falcated ducks in the dissemination of HPAIVs.

14.
Proc Natl Acad Sci U S A ; 118(4)2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33468660

RESUMEN

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common blood disorder, presenting multiple symptoms, including hemolytic anemia. It affects 400 million people worldwide, with more than 160 single mutations reported in G6PD. The most severe mutations (about 70) are classified as class I, leading to more than 90% loss of activity of the wild-type G6PD. The crystal structure of G6PD reveals these mutations are located away from the active site, concentrating around the noncatalytic NADP+-binding site and the dimer interface. However, the molecular mechanisms of class I mutant dysfunction have remained elusive, hindering the development of efficient therapies. To resolve this, we performed integral structural characterization of five G6PD mutants, including four class I mutants, associated with the noncatalytic NADP+ and dimerization, using crystallography, small-angle X-ray scattering (SAXS), cryogenic electron microscopy (cryo-EM), and biophysical analyses. Comparisons with the structure and properties of the wild-type enzyme, together with molecular dynamics simulations, bring forward a universal mechanism for this severe G6PD deficiency due to the class I mutations. We highlight the role of the noncatalytic NADP+-binding site that is crucial for stabilization and ordering two ß-strands in the dimer interface, which together communicate these distant structural aberrations to the active site through a network of additional interactions. This understanding elucidates potential paths for drug development targeting G6PD deficiency.


Asunto(s)
Coenzimas/química , Glucosafosfato Deshidrogenasa/química , Leucina/química , Mutación , NADP/química , Prolina/química , Sitios de Unión , Clonación Molecular , Coenzimas/metabolismo , Cristalografía por Rayos X , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Glucosafosfato Deshidrogenasa/genética , Glucosafosfato Deshidrogenasa/metabolismo , Deficiencia de Glucosafosfato Deshidrogenasa/enzimología , Deficiencia de Glucosafosfato Deshidrogenasa/genética , Deficiencia de Glucosafosfato Deshidrogenasa/patología , Humanos , Cinética , Leucina/metabolismo , Modelos Moleculares , Simulación de Dinámica Molecular , NADP/metabolismo , Prolina/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Multimerización de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidad por Sustrato
15.
J Am Chem Soc ; 142(35): 14933-14939, 2020 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-32786753

RESUMEN

The 6-deoxyerythronolide B synthase (DEBS) is a prototypical assembly line polyketide synthase (PKS) that synthesizes the macrocyclic core of the antibiotic erythromycin. Each of its six multidomain modules presumably sample distinct conformations, as biosynthetic intermediates tethered to their acyl carrier proteins interact with multiple active sites during the courses of their catalytic cycles. The spatiotemporal details underlying these protein dynamics remain elusive. Here, we investigate one aspect of this conformational flexibility using two domain-specific monoclonal antibody fragments (Fabs) isolated from a very large naïve human antibody library. Both Fabs, designated 1D10 and 2G10, were bound specifically and with high affinity to the ketoreductase domain of DEBS module 1 (KR1). Comparative kinetic analysis of stand-alone KR1 as well as a truncated bimodular derivative of DEBS revealed that 1D10 inhibited KR1 activity whereas 2G10 did not. Co-crystal structures of each KR1-Fab complex provided a mechanistic rationale for this difference. A hybrid PKS module harboring KR1 was engineered, whose individual catalytic domains have been crystallographically characterized at high resolution. Size exclusion chromatography coupled to small-angle X-ray scattering (SEC-SAXS) of this hybrid module bound to 1D10 provided further support for the catalytic relevance of the "extended" model of a PKS module. Our findings reinforce the power of monoclonal antibodies as tools to interrogate structure-function relationships of assembly line PKSs.


Asunto(s)
Aldo-Ceto Reductasas/metabolismo , Anticuerpos Monoclonales/metabolismo , Sondas Moleculares/metabolismo , Sintasas Poliquetidas/metabolismo , Aldo-Ceto Reductasas/química , Anticuerpos Monoclonales/química , Humanos , Lactonas/química , Lactonas/metabolismo , Conformación Molecular , Sondas Moleculares/química , Oxidación-Reducción , Sintasas Poliquetidas/química
16.
J Vet Med Sci ; 82(8): 1093-1096, 2020 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-32507786

RESUMEN

An adult male Hooded Crane was found dead on the Izumi plane. At autopsy, subcutaneous nodules were found around the medial and lateral sides of the left distal tibiotarsus bone. The largest cross-section of the masses revealed a multilobular pattern, with small amounts of viscous mucus. Histopathologically, the nodules were composed of three types of neoplastic cells: chondrocytic cells with abundant lightly basophilic cartilaginous matrices, mesenchymal cells and a small portion of the neoplastic tissue consisted of undifferentiated neoplastic cells exhibiting a high mitotic count and frequent multinucleation. This is the first case of a chondrosarcoma including undifferentiated neoplastic cell proliferation in a wild Hooded Crane.


Asunto(s)
Neoplasias Óseas/veterinaria , Condrosarcoma/veterinaria , Animales , Aves , Neoplasias Óseas/patología , Proliferación Celular , Condrosarcoma/patología , Japón , Masculino
17.
Arch Virol ; 165(3): 643-659, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31925543

RESUMEN

The Izumi plain in Kagoshima Prefecture, Japan, is an overwintering site for migratory ducks and endangered cranes. We have surveyed avian influenza viruses (AIVs) in this area since 2012 and isolated low-pathogenic AIVs (LPAIVs) of various subtypes every winter season. H3N8 LPAIVs were isolated during the 2012/13 and 2016/17 seasons, and H4N6 LPAIVs were isolated during the 2012/13 and 2013/14 seasons. In the 2017/18 season, one H3N8 and two H4N6 LPAIV strains were isolated from environmental water samples. Genetic and phylogenetic analysis for each gene segment from these H3N8 and H4N6 LPAIVs suggested that our isolates were genetic reassortants generated by intermixing between AIVs circulating not only in Eurasia but also in Africa and/or North America. Comparison of the genetic constellations of our three isolates with their counterparts isolated during previous seasons from the Izumi plain revealed a drastic transition in the genetic constellations of both subtypes. These findings emphasize the importance of continuous surveillance of AIVs on the Izumi plain.


Asunto(s)
Aves/virología , Patos/virología , Genoma Viral/genética , Subtipo H3N8 del Virus de la Influenza A/genética , Gripe Aviar/virología , África , Secuencia de Aminoácidos , Migración Animal , Animales , Animales Salvajes/virología , Secuencia de Bases , Europa (Continente) , Variación Genética/genética , Subtipo H3N8 del Virus de la Influenza A/aislamiento & purificación , Japón , América del Norte , Filogenia , Recombinación Genética/genética , Análisis de Secuencia de ARN
18.
Proc Natl Acad Sci U S A ; 117(1): 388-394, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31848245

RESUMEN

Surface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular self-assembly by crystallizing when exposed to an environmental trigger. However, molecular mechanisms governing rapid protein crystallization in vivo or in vitro are largely unknown. Here, we demonstrate that the Caulobacter crescentus SLP readily crystallizes into sheets in vitro via a calcium-triggered multistep assembly pathway. This pathway involves 2 domains serving distinct functions in assembly. The C-terminal crystallization domain forms the physiological 2-dimensional (2D) crystal lattice, but full-length protein crystallizes multiple orders of magnitude faster due to the N-terminal nucleation domain. Observing crystallization using a time course of electron cryo-microscopy (Cryo-EM) imaging reveals a crystalline intermediate wherein N-terminal nucleation domains exhibit motional dynamics with respect to rigid lattice-forming crystallization domains. Dynamic flexibility between the 2 domains rationalizes efficient S-layer crystal nucleation on the curved cellular surface. Rate enhancement of protein crystallization by a discrete nucleation domain may enable engineering of kinetically controllable self-assembling 2D macromolecular nanomaterials.


Asunto(s)
Proteínas Bacterianas/metabolismo , Caulobacter crescentus/metabolismo , Membrana Celular/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/ultraestructura , Calcio/metabolismo , Caulobacter crescentus/genética , Caulobacter crescentus/ultraestructura , Membrana Celular/química , Membrana Celular/ultraestructura , Microscopía por Crioelectrón , Cristalización , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/ultraestructura , Mutagénesis
19.
Proc Natl Acad Sci U S A ; 116(43): 21545-21555, 2019 10 22.
Artículo en Inglés | MEDLINE | ID: mdl-31591245

RESUMEN

The cadherin-catenin adhesion complex is the central component of the cell-cell adhesion adherens junctions that transmit mechanical stress from cell to cell. We have determined the nanoscale structure of the adherens junction complex formed by the α-catenin•ß-catenin•epithelial cadherin cytoplasmic domain (ABE) using negative stain electron microscopy, small-angle X-ray scattering, and selective deuteration/small-angle neutron scattering. The ABE complex is highly pliable and displays a wide spectrum of flexible structures that are facilitated by protein-domain motions in α- and ß-catenin. Moreover, the 107-residue intrinsically disordered N-terminal segment of ß-catenin forms a flexible "tongue" that is inserted into α-catenin and participates in the assembly of the ABE complex. The unanticipated ensemble of flexible conformations of the ABE complex suggests a dynamic mechanism for sensitivity and reversibility when transducing mechanical signals, in addition to the catch/slip bond behavior displayed by the ABE complex under mechanical tension. Our results provide mechanistic insight into the structural dynamics for the cadherin-catenin adhesion complex in mechanotransduction.


Asunto(s)
Cadherinas/química , Cadherinas/metabolismo , Mecanotransducción Celular , alfa Catenina/química , alfa Catenina/metabolismo , beta Catenina/química , beta Catenina/metabolismo , Uniones Adherentes/química , Uniones Adherentes/genética , Uniones Adherentes/metabolismo , Secuencias de Aminoácidos , Cadherinas/genética , Humanos , Conformación Molecular , Unión Proteica , Dominios Proteicos , Dispersión del Ángulo Pequeño , alfa Catenina/genética , beta Catenina/genética
20.
Virus Genes ; 55(6): 815-824, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31549291

RESUMEN

Viruses are believed to be ubiquitous; however, the diversity of viruses is largely unknown because of the bias of previous research toward pathogenic viruses. Deep sequencing is a promising and unbiased approach to detect viruses from animal-derived materials. Although cranes are known to be infected by several viruses such as influenza A viruses, previous studies targeted limited species of viruses, and thus viruses that infect cranes have not been extensively studied. In this study, we collected crane fecal samples in the Izumi plain in Japan, which is an overwintering site for cranes, and performed metagenomic shotgun sequencing analyses. We detected aviadenovirus-like sequences in the fecal samples and tentatively named the discovered virus crane-associated adenovirus 1 (CrAdV-1). We determined that our sequence accounted for approximately three-fourths of the estimated CrAdV-1 genome size (33,245 bp). The GC content of CrAdV-1 genome is 34.1%, which is considerably lower than that of other aviadenoviruses. Phylogenetic analyses revealed that CrAdV-1 clusters with members of the genus Aviadenovirus, but is distantly related to the previously identified aviadenoviruses. The protein sequence divergence between the DNA polymerase of CrAdV-1 and those of other aviadenoviruses is 45.2-46.8%. Based on these results and the species demarcation for the family Adenoviridae, we propose that CrAdV-1 be classified as a new species in the genus Aviadenovirus. Results of this study contribute to a deeper understanding of the diversity and evolution of viruses and provide additional information on viruses that infect cranes, which might lead to protection of the endangered species of cranes.


Asunto(s)
Infecciones por Adenoviridae/genética , Aviadenovirus/genética , Enfermedades de las Aves/genética , Infecciones por Adenoviridae/virología , Animales , Aviadenovirus/aislamiento & purificación , Enfermedades de las Aves/virología , Aves/genética , Aves/virología , Heces/virología , Secuenciación de Nucleótidos de Alto Rendimiento , Virus de la Influenza A/genética , Virus de la Influenza A/patogenicidad , Japón , Filogenia
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