|
|
Biophysical Characterization of Coronaviral nsp14 Inhibition
Trembulaková, Pavla ; Bouřa, Evžen (advisor) ; Dejmek, Milan (referee)
RNA virus SARS-CoV-2 caused worldwide pandemic of severe disease COVID-19 which lasted more than a year. Repair mechanisms of this virus during replication process significantly reduce efficiency of nucleotide analog drugs, eg. remdesivir. Nonstructural protein (nsp) 14 and nsp10 form a complex which acts as an exonuclease enzyme and will be furthrer referred to as an ExoN complex. This complex can probably cause lower efficiency of incorporation of nucleotide analogs compared to viruses without exonuclease enzymes. The two-protein complex with active site on nsp14 containing two magensium ions seems like a good target for testing potent inhobitors. Among possible inhibitors of SARS-CoV-2 exonuclease complex are isobavachalcone and sofalcone. According to published studies, those small organic molecules chelate magensium ions in active site of exonulease part in nsp14. This results in inactivation of ExoN complex active site in nsp14 structure and disables the catalytic function which acts as repairing element in RNA synthesis process. This tesis focuses on characterization of inhibition of protein complex nsp14 and nsp10 in presence of small selected molecules, isobavachalcone and sofalcone. Exonuclease activity assays in presence of various RNA substrates were performed. Furthermore, there have been...
|
|
| |
|
|
Synthesis of novel conformationally locked carbocyclic nucleosides derived from 2-(hydroxymethyl)bicyclo[2.2.1]heptane
Dejmek, Milan
58 Abstract A new synthetic pathway to novel conformationally locked carbocyclic nucleosides containing 2-(hydroxymethyl)bicyclo [2.2.1]heptane was elaborated. (1R*,2R*,4R*,6R*)-6- and (1R*,2R*,4R*,5S*)-5- (Hydroxymethyl)bicyklo[2.2.1]heptan-2-ol was synthetised as a key intermediate from comertially available dicyclopentadiene and methylacrylate. Racemic karbocyclic nukleosides (1R*,2R*,4S*,6S*)-6- and [(1R*,2S*,4R*,5S*)-5-(6-chloro-9H-purin-9-yl)bicyclo[2.2.1]hept-2-yl]methanol were synthetised by Mitsunobu reaction of (1R*,2R*,4R*,6R*)-6- or (1R*,2R*,4R*,5S*)-5-(hydroxymethyl)bicyclo[2.2.1]heptan-2-ol with 6-chlorpurine. Racemic karbocyclic nukleosides bearing adenine ring, 6-cyclopropylaminopurine ring, 6-dimethylaminopurine ring or 6-thiopurine ring were synthetised by substitution of chlorine of 6-chlorpurine ring. Racemic karbocyclic nukleosides bearing thymine ring (1- [(1R*,2S*,4S*,6R*)-6- and 1-[(1R*,2S*,4R*,5S*)-5- (hydroxymethyl)bicyclo[2.2.1]hept-2-yl]-5-methylpyrimidine-2,4(1H,3H)-dione) were synthetised by reaction of 5- or 6-aminobicyclo[2.2.1]hept-2-yl methanol with ethyl [(2E)-3-ethoxy-2-methylprop-2-enoyl]carbamate. The 5- or 6- aminobicyclo[2.2.1]hept-2-yl methanol was prepared in three simple steps from the key intermediate 5- or 6-(hydroxymethyl)bicyclo[2.2.1]heptan-2-ol. All...
|
|
| |
|
|
Conformationally locked carbocyclic nucleoside analogues.
Dejmek, Milan ; Hřebabecký, Hubert (advisor) ; Černý, Miloslav (referee) ; Moravcová, Jitka (referee)
Three novel series of conformationally locked carbocyclic nucleoside analogues based on the bridgehead substituted norbornane bicyclic skeleton were prepared - analogues with the pseudosugar locked in the North, East or South conformation. These compounds were synthesized as structurally related substances to a commercially successful antiviral drug abacavir, which is used in the therapy of HIV. One of the goals was the exploration of the dependence of antiviral activities of prepared compounds on the conformation of their pseudosugar part. The key intermediates in the syntheses of the North and South analogues, amine precursors suitable for nucleobase construction, were prepared in several steps from easily accessible 5-carboxymethyl norbornene. Introduction of a carboxylic function into the bridgehead position, a key transformation mutual to both syntheses, was accomplished via the Hell-Volhard-Zelinsky bromination of norbornane-2- carboxylic acid, which affords rearranged 2-exo-bromo-1-carboxynorbornane. Approach to the derivatives locked in the East conformation is based on radical cyclization of substituted 4-(bromomethyl)cyclohexanone oxime, which affords norbornane intermediate substituted in both bridgehead positions. Thymine, 6-chloropurine and 2-amino-6-chloropurine nucleobases were used...
|
|
|
Synthesis of novel conformationally locked carbocyclic nucleosides derived from 2-(hydroxymethyl)bicyclo[2.2.1]heptane
Dejmek, Milan
58 Abstract A new synthetic pathway to novel conformationally locked carbocyclic nucleosides containing 2-(hydroxymethyl)bicyclo [2.2.1]heptane was elaborated. (1R*,2R*,4R*,6R*)-6- and (1R*,2R*,4R*,5S*)-5- (Hydroxymethyl)bicyklo[2.2.1]heptan-2-ol was synthetised as a key intermediate from comertially available dicyclopentadiene and methylacrylate. Racemic karbocyclic nukleosides (1R*,2R*,4S*,6S*)-6- and [(1R*,2S*,4R*,5S*)-5-(6-chloro-9H-purin-9-yl)bicyclo[2.2.1]hept-2-yl]methanol were synthetised by Mitsunobu reaction of (1R*,2R*,4R*,6R*)-6- or (1R*,2R*,4R*,5S*)-5-(hydroxymethyl)bicyclo[2.2.1]heptan-2-ol with 6-chlorpurine. Racemic karbocyclic nukleosides bearing adenine ring, 6-cyclopropylaminopurine ring, 6-dimethylaminopurine ring or 6-thiopurine ring were synthetised by substitution of chlorine of 6-chlorpurine ring. Racemic karbocyclic nukleosides bearing thymine ring (1- [(1R*,2S*,4S*,6R*)-6- and 1-[(1R*,2S*,4R*,5S*)-5- (hydroxymethyl)bicyclo[2.2.1]hept-2-yl]-5-methylpyrimidine-2,4(1H,3H)-dione) were synthetised by reaction of 5- or 6-aminobicyclo[2.2.1]hept-2-yl methanol with ethyl [(2E)-3-ethoxy-2-methylprop-2-enoyl]carbamate. The 5- or 6- aminobicyclo[2.2.1]hept-2-yl methanol was prepared in three simple steps from the key intermediate 5- or 6-(hydroxymethyl)bicyclo[2.2.1]heptan-2-ol. All...
|
|
|
Novel conformationally locked nucleosides and nucleotides based on bicyclo[3.2.1]octane scaffold as a pseudosugar moiety
Šála, Michal ; Dejmek, Milan ; Procházková, Eliška ; Hřebabecký, Hubert ; Rybáček, Jiří ; Dračínský, Martin ; Novák, Pavel ; Rosenbergová, Šárka ; Fukal, J. ; Sychrovský, Vladimír ; Rosenberg, Ivan ; Nencka, Radim
A route to a series of novel carbocyclic nucleosides locked in North conformation with bicyclo[3.2.1]octane scaffold was developed. Prepared nucleosides served as a starting material for the synthesis of modified oligomers [d(GCATATCAC), r(GCAUAUCAC), and A9]. Biological effects of the prepared nucleosides as well as the hybridization properties of the appropriate duplexes were evaluated.
|
|
| |
guest ::
RSS feed.