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Order Tubulavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
In parallel, Welsh et al. (1998) recorded x-ray diffraction patterns at 3.1 Å resolution from magnetically aligned fibres of the phage Pf3, a member of the Pseudomonas virus Pf3 species from the Tertilicivirus genus. The patterns indicated that the Pf3 and the previously described Pf1 virions had the same helix symmetry and similar protein subunit shape. This was of particular interest, given that the primary structures of the two protein subunits and the nucleotide/protein subunit ratios were quite different. As a result, the molecular model of the Pf3 protein capsid was built on the basis of the Pf1 model. Remarkably, the Pf3 subunit appeared to be completely α-helical, beginning at the N-terminus, whereas the first few residues of the Pf1 subunit were not helical (Welsh et al. 1998).
Vaccine Development Strategies and the Current Status of COVID-19 Vaccines
Published in Debmalya Barh, Kenneth Lundstrom, COVID-19, 2022
Mohsen Akbarian, Kenneth Lundstrom, Elrashdy M. Redwan, Vladimir N. Uversky
Protein subunit vaccines target viral or bacterial proteins as antigens. So far, these vaccines have been developed against hepatitis B, meningitis, and pneumonia viruses, as well as many bacterial pathogens, such as tetanus, diphtheria, pertussis (whooping cough), and meningitis caused by Haemophilus influenzae type b (Hib). In the case of SARS-CoV, different viral proteins, including nucleocapsid protein, the RBD of the S protein, and the full-length S protein have been used as antigens. These types of vaccines have attracted considerable attention because they can produce favourable immune responses without the presence of actual viral genetic material. However, since the virus components are no longer present in these vaccines, the responses are naturally accompanied by a significant delay, which has led to the use of these vaccines along with adjuvants [12, 35]. Protein subunit vaccines based on expression of the full-length or a truncated form of the SARS-COV-2 S protein in Drosophila S2 and Spodoptera frugiperda Sf9 insect cells has elicited neutralizing antibody responses in animal models [36].
Antiviral Agents and Rational Drug Design
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Studies of the enzymes crystal structure using x-ray diffraction and molecular modelling revealed that neuraminidase is a mushroom-shaped tetrameric glycoprotein, attached to the viral membrane by a single hydrophobic sequence consisting of 29 amino acids, which can be cleaved from the surface enzymatically to enable the unadulterated polypeptide to be studied without loss of antigenic or enzymatic activity. It was found that the active site is a deep pocket located centrally on each protein subunit; composed of 18 amino acids that are highly conserved. The outer structure of the protein is much more variable.
Emerging antiviral therapies and drugs for the treatment of influenza
Published in Expert Opinion on Emerging Drugs, 2022
Jinshen Wang, Yihang Sun, Shuwen Liu
It is widely thought that RNA polymerase, HA and NP are new targets for influenza therapeutic research, and the compounds acting on these influenza virus components can work on key processes in the viral replication cycle. PB2, PB1 and PA proteins are components of the influenza virus polymerase complex: PA has endonuclease activity and combines with viral RNA promoter, while PB2 can connect with the host mRNA precursor to begin transcription. These three protein subunits are highly conserved and rarely variable so that it is hard to produce drug resistance, leading to a widespread concern of the related inhibitors [26,27]. HA is reportedly involved in viral attachment and membrane fusion, making it a potential target for antiviral drugs. Although high antigenic variations in HA among different subtypes of IAVs limit the development of broad-spectrum inhibitors, an increasing number of highly potent inhibitors targeting HA have been discovered [28]. NP of the influenza virus plays an essential part in viral replication, mainly involving RNA accumulation, transcription and nuclear transport. Moreover, the basic structure of NP is relatively conserved, suggesting that the virus cannot easily develop drug resistance.
The Association between Consumption of Dairy-Originated Digestion Resistant and Bioactive Peptides and Breast Cancer Risk: A Case-Control Study
Published in Nutrition and Cancer, 2022
Masoumeh Jabbari, Meisam Barati, Mahdi Shabani, Elham Kazemian, Sajad Khalili-Moghadam, Fardin Javanmardi, Elaheh Hatami, Reihaneh Zeinalian, Sayed Hossein Davoodi, Bahram Rashidkhani, Shima Jafarzadeh, Elcin Huseyn, Amin Mousavi Khaneghah
The dietary intake of BPs was estimated based on dairy food items in the FFQ (26). Calculation of bioactive and digestion-resistant peptides intake was performed by multiplying dairy items intake (g) by the content of their bioactive and digestion-resistant peptides. The method of BP content estimation was developed and validated in our previous in silico study (28). In brief, simulated proteolysis of the dairy protein subunits was conducted using the "enzyme action" tool of the BIOPEP web server (29). First, in silico, proteolysis of proteins was conducted using pepsin, trypsin, and chymotrypsin A. Then, the peptide fragments resulting from proteolysis of αs1-casein, αs2-casein, β-casein, k-casein, β-lactoglobulin, and α-lactalbumin were submitted to the BIOPEP database to characterize active fragments. Finally, the sequences obtained from in silico digestion were separated according to (1) total peptides, (2) biological function (anti-diabetic, anti-hypertensive, antioxidant, and immunomodulatory), (3) number of residues (di, tri, tetra, penta, hexa, hepta, and more than heptapeptide), (4) hydrophilicity (low and high), and (5) bioactivity (low and high).
Targeted IgMs agonize ocular targets with extended vitreal exposure
Published in mAbs, 2020
Yvonne Chen, Maciej Paluch, Julie A. Zorn, Sharmila Rajan, Brandon Leonard, Alberto Estevez, John Brady, Henry Chiu, Wilson Phung, Amin Famili, Minhong Yan, Claudio Ciferri, Marissa L. Matsumoto, Greg A. Lazar, Susan Crowell, Phil Hass, Nicholas J. Agard
IgMs are megadalton-sized protein complexes of 21 or 24 protein subunits. By molecular weight they are 6–7x larger than an IgG and approximately 20x larger than an antigen-binding fragment (Fab). The ‘monomeric’ component of an IgM consists of two light chains (LCs), each containing two Ig-domains, and two heavy chains (HCs), containing five Ig-domains and a short C-terminal tail piece (CTP, Figure 1a).10 These four chains assemble to form a homodimer of HC-LC heterodimers. Subsequently, disulfide formation and folding of the C-terminal tail-piece into beta-strands drives formation of pentamers containing five homodimers and a J-chain (JC) or hexamers with six homodimers. In humans, pentamers are the dominant species, accounting for ~95−98% of the IgMs isolated from serum.11 These four chains assemble to form a homodimer of HC-LC heterodimers. Subsequently, disulfide formation and folding of the C-terminal tail-piece into beta-strands drives formation of pentamers containing five homodimers and a J-chain (JC) or hexamers with six homodimers. In humans, pentamers are the dominant species, accounting for ~95−98% of the IgMs isolated from serum.,11–13 It is believed that avid binding of 10 or 12 variable fragments (Fvs) enables IgMs to bind targets without substantial affinity maturation, and thus to serve as sentinel adaptive immune receptors.12,13