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Order Articulavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
First, the x-ray crystal structure of the N-terminal portion of the M1 protein of the influenza A/PR/8/34 (H1N1) virus was determined at 2.08 Å resolution (Sha and Luo 1997). This structure revealed that residues 2–158 of the 258-residue-long M1 fold into two domains, the N-terminal and the middle M ones, each of which contained four α-helices. The protein formed a dimer. The highly positively charged region on the dimer surface was positioned to bind RNA while the hydrophobic surface opposite the RNA binding region was involved in interactions with the membrane.
Renal Drug-Metabolizing Enzymes in Experimental Animals and Humans
Published in Robin S. Goldstein, Mechanisms of Injury in Renal Disease and Toxicity, 2020
The initial step in GSH conjugation of xenobiotics is catalyzed by a family of primarily soluble enzymes GSH 5-transferases, although membrane-bound forms have been isolated and identified (Morganstem and DePierre, 1988). In those species so far investigated there is a multiplicity of soluble forms, and amino acid sequence data deduced from cDNA clones suggest that all soluble GSH S-transferases are dimers of subunits of molecular weight from 20 to 25 kDa (Taylor et al., 1987). Within a dimer, each subunit functions independently of the other (Mannervik and Jensson, 1982). The most thoroughly studied species is the rat, followed by man, and these species are reviewed in this article.
Chikungunya Fever: Emergence and Reality
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Neelam Yadav, Bennet Angel, Jagriti Narang, Surender Singh Yadav, Vinod Joshi
This protein is initially synthesized as a hydrophilic monomer but later changes to a hydrophobic dimer, which has two of its N-glycans modified on reaching the Golgi bodies to obtain a complex structure. The dimer has three domains: a β-roll domain, a Wing domain, and a β-ladder domain (see Fig. 4.11). Due to its varied role, it is now being used for experiment by researchers across the world for its utility as a target for antiviral therapy.
F11R/JAM-A: why do platelets express a molecule which is also present in tight junctions?
Published in Platelets, 2023
Piotr Kamola, Anna Babinska, Tomasz Przygodzki
As mentioned above, F11R/JAM-A molecules are capable of forming homodimers. This homodimerization occurs in cis-configuration when the dimer is formed by the molecules located in the same cell (Figure 2b). The molecules can also interact in the trans-configuration when they are located on the membrane of two adjacent cells20 (Figure 2c). It is not clear whether cis-homodimerization is required for trans-homophilic interactions. Some data suggest that monomeric F11R/JAM-A can also interact with its counterpart on an adjacent cell.20 The sites responsible for cis- and trans-homophilic interactions lay in distinct parts of D1 domain of the molecule.20 Both types of interactions are believed to be associated with the function of the protein which will be described further.
Insights into the operational model of agonism of receptor dimers
Published in Expert Opinion on Drug Discovery, 2022
There are two kinds of dimers (Figure 1). Homodimers (Figure 1, left) consist of two identical receptors R for which a given agonist A has the same affinity (1/KA) and exerts the same operational efficacy τ. Two molecules of an agonist bound to two orthosteric binding sites exert allosteric interaction. The factor of binding cooperativity α quantifies the change in agonist affinity upon binding of the second molecule of agonist to the dimer. In the case of positive cooperativity, the affinity of two concurrently bound agonists is greater than the affinity of a single bound agonist and the value of binding cooperativity factor α is higher than 1. In the case of negative cooperativity, the affinity of two concurrently bound agonist molecules is smaller than the affinity of a single bound molecule and the value of binding cooperativity factor α is lower than 1. The change in operational efficacy τ upon binding of the second molecule of agonist to the dimer is quantified by efficacy cooperativity factor β. In analogy to binding cooperativity, values of β higher than 1 denote positive cooperativity leading to an increase in operational efficacy τ and values lower than 1 denote negative cooperativity leading to a decrease in τ.
An alternative non-proteolytic mechanism may underlie AGel amyloidosis
Published in Amyloid, 2019
Francesco Bonì, Mario Milani, Eloise Mastrangelo, Alberto Babiroli, Luisa Diomede, Matteo de Rosa
Structural analysis of the G167R variant revealed that this mutant can dimerize through a peculiar domain swapping mechanism [6]. Dimer and monomer are in dynamic equilibrium in solution and several factors, such as temperature, protein and calcium concentration, affect the equilibrium and the kinetics of interconversion between the two forms. In the absence of calcium, the dimeric form is favoured. These data suggest that, in addition to the proteolytic pathway, an alternative non-proteolytic mechanism, triggered by G167R oligomerization, may participate in GSN misfolding and aggregation (Figure 1, oligomerization pathway). Whether these assemblies are prone to form amyloidogenic assemblies alone or need to be primed, for example by the circulating GSN fragments, remains to be tested.