scholarly journals Binding Mechanism Elucidation of the Acute Respiratory Disease Causing Agent Adenovirus of Serotype 7 to Desmoglein-2

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1075
Author(s):  
Marc-André Hograindleur ◽  
Gregory Effantin ◽  
Daphna Fenel ◽  
Caroline Mas ◽  
André Lieber ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
The United States ◽  
Cellular Receptor ◽  
Amino Acid Residues ◽  
Binding Mechanism ◽  
Acute Respiratory Disease ◽  
Critical Amino Acid ◽  
Cryo Electron Microscopy ◽  
Virus Life Cycle ◽  
Global Pandemic

The study of viruses causing acute respiratory distress syndromes (ARDS) is more essential than ever at a time when a virus can create a global pandemic in a matter of weeks. Among human adenoviruses, adenovirus of serotype 7 (HAdV7) is one of the most virulent serotypes. This virus regularly re-emerges in Asia and has just been the cause of several deaths in the United States. A critical step of the virus life cycle is the attachment of the knob domain of the fiber (HAd7K) to the cellular receptor desmoglein-2 (DSG2). Complexes between the fiber knob and two extracellular domains of DSG2 have been produced. Their characterization by biochemical and biophysical methods show that these two domains are sufficient for the interaction and that the trimeric HAd7K could accommodate up to three DSG2 receptor molecules. The cryo-electron microscopy (cryo-EM) structure of these complexes at 3.1 Å resolution confirmed the biochemical data, and allowed the identification of the critical amino acid residues for this interaction, which shows similarities with other DSG2 interacting adenoviruses, despite a low homology in the primary sequences.

scholarly journals Cryo-electron microscopy studies of empty capsids of human parvovirus B19 complexed with its cellular receptor.

1996 ◽  
Vol 93 (15) ◽  
pp. 7502-7506 ◽  
Author(s):  
P. R. Chipman ◽  
M. Agbandje-McKenna ◽  
S. Kajigaya ◽  
K. E. Brown ◽  
N. S. Young ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Parvovirus B19 ◽  
Cellular Receptor ◽  
Human Parvovirus B19 ◽  
Cryo Electron Microscopy

scholarly journals Cryo-electron Microscopy Study of the Genome Release of the Dicistrovirus Israeli Acute Bee Paralysis Virus

2016 ◽  
Vol 91 (4) ◽  
Author(s):  
Edukondalu Mullapudi ◽  
Tibor Füzik ◽  
Antonín Přidal ◽  
Pavel Plevka
Keyword(s):  
Electron Microscopy ◽  
The United States ◽  
Capsid Proteins ◽  
Content Type ◽  
Cryo Electron Microscopy ◽  
The Family ◽  
Electron Microscopy Analysis ◽  
Colony Collapse ◽  
Acute Bee Paralysis Virus ◽  
Paralysis Virus

ABSTRACT Viruses of the family Dicistroviridae can cause substantial economic damage by infecting agriculturally important insects. Israeli acute bee paralysis virus (IAPV) causes honeybee colony collapse disorder in the United States. High-resolution molecular details of the genome delivery mechanism of dicistroviruses are unknown. Here we present a cryo-electron microscopy analysis of IAPV virions induced to release their genomes in vitro. We determined structures of full IAPV virions primed to release their genomes to a resolution of 3.3 Å and of empty capsids to a resolution of 3.9 Å. We show that IAPV does not form expanded A particles before genome release as in the case of related enteroviruses of the family Picornaviridae. The structural changes observed in the empty IAPV particles include detachment of the VP4 minor capsid proteins from the inner face of the capsid and partial loss of the structure of the N-terminal arms of the VP2 capsid proteins. Unlike the case for many picornaviruses, the empty particles of IAPV are not expanded relative to the native virions and do not contain pores in their capsids that might serve as channels for genome release. Therefore, rearrangement of a unique region of the capsid is probably required for IAPV genome release. IMPORTANCE Honeybee populations in Europe and North America are declining due to pressure from pathogens, including viruses. Israeli acute bee paralysis virus (IAPV), a member of the family Dicistroviridae, causes honeybee colony collapse disorder in the United States. The delivery of virus genomes into host cells is necessary for the initiation of infection. Here we present a structural cryo-electron microscopy analysis of IAPV particles induced to release their genomes. We show that genome release is not preceded by an expansion of IAPV virions as in the case of related picornaviruses that infect vertebrates. Furthermore, minor capsid proteins detach from the capsid upon genome release. The genome leaves behind empty particles that have compact protein shells.

scholarly journals Cryo-EM structure of the tetracycline resistance protein TetM in complex with a translating ribosome at 3.9-Å resolution

2015 ◽  
Vol 112 (17) ◽  
pp. 5401-5406 ◽  
Author(s):  
Stefan Arenz ◽  
Fabian Nguyen ◽  
Roland Beckmann ◽  
Daniel N. Wilson
Keyword(s):  
Electron Microscopy ◽  
Amino Acid ◽  
16S Rrna ◽  
Binding Site ◽  
Tetracycline Resistance ◽  
Small Subunit ◽  
Amino Acid Residues ◽  
Tyrosine Residues ◽  
Cryo Electron Microscopy ◽  
Resistance Protein

Ribosome protection proteins (RPPs) confer resistance to tetracycline by binding to the ribosome and chasing the drug from its binding site. Current models for RPP action are derived from 7.2- to 16-Å resolution structures of RPPs bound to vacant or nontranslating ribosomes. Here we present a cryo-electron microscopy reconstruction of the RPP TetM in complex with a translating ribosome at 3.9-Å resolution. The structure reveals the contacts of TetM with the ribosome, including interaction between the conserved and functionally critical C-terminal extension of TetM with a unique splayed conformation of nucleotides A1492 and A1493 at the decoding center of the small subunit. The resolution enables us to unambiguously model the side chains of the amino acid residues comprising loop III in domain IV of TetM, revealing that the tyrosine residues Y506 and Y507 are not responsible for drug-release as suggested previously but rather for intrafactor contacts that appear to stabilize the conformation of loop III. Instead, Pro509 at the tip of loop III is located directly within the tetracycline binding site where it interacts with nucleotide C1054 of the 16S rRNA, such that RPP action uses Pro509, rather than Y506/Y507, to directly dislodge and release tetracycline from the ribosome.

scholarly journals Architecture of a SARS-CoV-2 mini replication and transcription complex

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Liming Yan ◽  
Ying Zhang ◽  
Ji Ge ◽  
Litao Zheng ◽  
Yan Gao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Life Cycle ◽  
Structural Proteins ◽  
Helicase Activity ◽  
Rna Dependent Rna Polymerase ◽  
Cryo Electron Microscopy ◽  
Virus Life Cycle ◽  
Primer Rna ◽  
Insight Into ◽  
Variable Interactions

AbstractNon-structural proteins (nsp) constitute the SARS-CoV-2 replication and transcription complex (RTC) to play a pivotal role in the virus life cycle. Here we determine the atomic structure of a SARS-CoV-2 mini RTC, assembled by viral RNA-dependent RNA polymerase (RdRp, nsp12) with a template-primer RNA, nsp7 and nsp8, and two helicase molecules (nsp13-1 and nsp13-2), by cryo-electron microscopy. Two groups of mini RTCs with different conformations of nsp13-1 are identified. In both of them, nsp13-1 stabilizes overall architecture of the mini RTC by contacting with nsp13-2, which anchors the 5′-extension of RNA template, as well as interacting with nsp7-nsp8-nsp12-RNA. Orientation shifts of nsp13-1 results in its variable interactions with other components in two forms of mini RTC. The mutations on nsp13-1:nsp12 and nsp13-1:nsp13-2 interfaces prohibit the enhancement of helicase activity achieved by mini RTCs. These results provide an insight into how helicase couples with polymerase to facilitate its function in virus replication and transcription.

scholarly journals Interaction of Decay-Accelerating Factor with Echovirus 7

2010 ◽  
Vol 84 (24) ◽  
pp. 12665-12674 ◽  
Author(s):  
Pavel Plevka ◽  
Susan Hafenstein ◽  
Katherine G. Harris ◽  
Javier O. Cifuente ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Binding Site ◽  
Symmetry Axis ◽  
Cellular Receptor ◽  
Icosahedral Symmetry ◽  
Decay Accelerating Factor ◽  
Cryo Electron Microscopy ◽  
The Family ◽  
Initial Process

ABSTRACT Echovirus 7 (EV7) belongs to the Enterovirus genus within the family Picornaviridae. Many picornaviruses use IgG-like receptors that bind in the viral canyon and are required to initiate viral uncoating during infection. However, in addition, some of the enteroviruses use an alternative or additional receptor that binds outside the canyon. Decay-accelerating factor (DAF) has been identified as a cellular receptor for EV7. The crystal structure of EV7 has been determined to 3.1-Å resolution and used to interpret the 7.2-Å-resolution cryo-electron microscopy reconstruction of EV7 complexed with DAF. Each DAF binding site on EV7 is near a 2-fold icosahedral symmetry axis, which differs from the binding site of DAF on the surface of coxsackievirus B3, indicating that there are independent evolutionary processes by which DAF was selected as a picornavirus accessory receptor. This suggests that there is an advantage for these viruses to recognize DAF during the initial process of infection.

scholarly journals Atomic structure of human sapovirus capsid by single particle cryo-electron microscopy

2021 ◽  
Author(s):  
Naoyuki Miyazaki ◽  
Kosuke Murakami ◽  
Tomoichiro Oka ◽  
Motohiro Miki ◽  
Kenji Iwasaki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Atomic Structure ◽  
Single Particle ◽  
Structural Information ◽  
Amino Acid Residues ◽  
Diagnostic Systems ◽  
Important Amino Acid ◽  
Hypervariable Regions ◽  
Cryo Electron Microscopy ◽  
Domain Interactions

SummarySapovirus is a cause of acute gastroenteritis in humans and animals. Infants and younger children have the greatest disease burden. Although it shares many similarities with norovirus, the lack of detailed structural information has hampered the development of vaccines and therapeutics. Here, we investigated the human sapovirus VLP by single particle cryo-electron microscopy and are the first to report the atomic structure of the capsid at 2.9 Å resolution. The atomic model revealed the domain interactions of the capsid protein and functionally important amino acid residues. The extended loop from the P1 subdomain was involved in interactions in the P2 domain, forming unique arch-like dimeric protrusions of capsid proteins. All hypervariable regions that are important candidates for immune response or receptor binding, formed a large cluster at the top of the P domain. These results pave the way for developing vaccines, antiviral drugs, and diagnostic systems for this infectious disease.

New challenges to image processing posed by cryo-Electron microscopy of single particles

1991 ◽  
Vol 49 ◽  
pp. 422-423
Author(s):  
Joachim Frank
Keyword(s):  
Electron Microscopy ◽  
Phase Contrast ◽  
Particle Orientation ◽  
Single Particles ◽  
Contrast Transfer Function ◽  
Virtual Absence ◽  
Cryo Electron Microscopy ◽  
Spatial Frequencies ◽  
New Challenges ◽  
Particle Images

Compared with images of negatively stained single particle specimens, those obtained by cryo-electron microscopy have the following new features: (a) higher “signal” variability due to a higher variability of particle orientation; (b) reduced signal/noise ratio (S/N); (c) virtual absence of low-spatial-frequency information related to elastic scattering, due to the properties of the phase contrast transfer function (PCTF); and (d) reduced resolution due to the efforts of the microscopist to boost the PCTF at low spatial frequencies, in his attempt to obtain recognizable particle images.

Enhanced information from biological materials through technological improvements in cryo-electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 788-789
Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Biological Materials ◽  
Electron Crystallography ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
The Many ◽  
Technological Improvements ◽  
Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

Study of eukaryotic flagellar components by cryo-electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 98-101
Author(s):  
John M. Murray ◽  
Rob Ward
Keyword(s):  
Electron Microscopy ◽  
Primary Motion ◽  
Cryo Electron Microscopy ◽  
Cross Links ◽  
Cilia And Flagella

The eukaryotic flagellum is constructed from 11 parallel tubular elements arranged as 9 peripheral fibers (doublet microtubules) and 2 central fibers (singlet microtubules). The primary motion generating component has been found to be arranged as axially periodic “arms” bridging the adjacent doublets. The dynein, comprising the arms, has been isolated and characterized from several different cilia and flagella. Various radial and azimuthal cross-links stabilize the axially aligned microtubules, and probably play some role in controlling the form of the flagella beat cycle.

Scanning electron microscopy of asbestos-containing material where the asbestos fibers are considered locked in a binder

1993 ◽  
Vol 51 ◽  
pp. 472-473
Author(s):  
J. R. Millette ◽  
R. S. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Protection Agency ◽  
Building Materials ◽  
The United States ◽  
Protection Agency ◽  
Asbestos Fibers ◽  
Different Types ◽  
Binder Material ◽  
Scanning Electron

The United States Environmental Protection Agency (EPA) has labeled as “friable” those building materials that are likely to readily release fibers. Friable materials when dry, can easily be crumbled, pulverized, or reduced to powder using hand pressure. Other asbestos containing building materials (ACBM) where the asbestos fibers are in a matrix of cement or bituminous or resinous binders are considered non-friable. However, when subjected to sanding, grinding, cutting or other forms of abrasion, these non-friable materials are to be treated as friable asbestos material. There has been a hypothesis that all raw asbestos fibers are encapsulated in solvents and binders and are not released as individual fibers if the material is cut or abraded. Examination of a number of different types of non-friable materials under the SEM show that after cutting or abrasion, tuffs or bundles of fibers are evident on the surfaces of the materials. When these tuffs or bundles are examined, they are shown to contain asbestos fibers which are free from binder material. These free fibers may be released into the air upon further cutting or abrasion.

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