Browsing by Subject "binding affinity"

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    Effects of Active Site Inhibitors on APN-dependent Coronavirus Entry
    (2017-06) Cai, Yijian
    Aminopeptidase N(APN) has been shown as a receptor of several coronaviruses, such as HCoV-229E, TGEV, CCoV and FeCoV. Bestatin and Actinonin are inhibitors which can block APN enzymatic activity. These inhibitors bind to the catalytic site of APN, while viruses bind to the outer surface of APN. Here we investigate the mechanism of APN inhibition on protein-protein binding, receptor expression and coronavirus entry. We find that these chemical compounds can inhibit the protein-protein interaction between APN and Coronavirus spike; these inhibitors can also regulate APN RNA and protein expression; additionally, these compounds can inhibit the pseudovirus entry of HCoV-229E into human cells at a certain level. Additionally, coronavirus spike-treated human cells show a decrease in APN expression. This phenomenon may reveal an adaptation of cells to the different treatments and conditions. Our research may provide a new potential strategy for antiviral treatment.
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    Quantification and Analysis of Tau Protein Effects on Microtubule Dynamics in Mammalian (LLC-PK1) Cells
    (2020-07) Doersch, Alexandra
    Overall, we found that multiple biophysical properties of tau protein affect MT dynamics in LLC-PK1 cells; various isoforms exhibit differential effects. 2N4R tau exhibits MT tip avoidance (~200 nm) during growth that is lost for 0N4R tau. 2N4R and 0N4R tau phenocopy MTAs to make MTs less dynamic via different processes. We propose 2N4R tau has at least two binding sites, one of higher and one of lower affinity, resulting in KD=0.31 µM that preferentially associates with GDP-tubulin lattice to enable growing tip avoidance. 0N4R tau loses access to higher but retains lower affinity binding, resulting in KD=3.2 µM. Uniquely, 0N4R P301L tau does not bind to MTs (KD>>10 µM), indicating loss of both higher and lower affinity binding, perhaps due to induced conformation changes. Possible implications for tauopathies include the decreased ability of 0N4R P301L tau to bind to MTs, which may promote disease-associated progression toward tau oligomerization.