Abstract
Protein methylation and acetylation hold immense biological significance, and the methyltransferases
and acetyltransferases that are responsible for these processes have been implicated in multiple diseases.
Thus, in this dissertation, our focus was turned on co-substrate competitive inhibition. We aimed to probe
the co-substrate binding pockets of biomedically important protein methyltransferases and
acetyltransferases, based on the structures of S-adenosyl-L-homocysteine and coenzyme A, the byproducts and pan-inhibitors of the enzymatic methylation and acetylation reactions, respectively. This
work allowed us to explore the potential for discovery of potent and selective inhibitors for these
enzymes.
Chapter 3 focuses on selected modifications on S-adenosyl-L-homocysteine for inhibition of human histidine methyltransferase SETD3, as well as histone lysine methyltransferases GLP, G9a and SETD8. We discovered that disruption of the hydrogen bond pattern in the N6-adenine moiety has a dramatic effect on the inhibition potency, however, selenated analogue SeAH was identified as a potent inhibitor for all screened enzymes, with IC50 values of 12.0 μM for SETD3, 116 nM for GLP, 1.8 μM for G9a and 452 nM for SETD8.
Chapter 4 covers the design and synthesis of a unique redox-labile S-adenosyl-L-homocysteine analog, SS-SAH, which possesses a disulfide bond. This compound showed inhibitory activity, with IC50 values of 30.4 μM for GLP, 95.4 μM for G9a and 4.4 μM for SETD8. Docking studies and biomolecular simulations provided insight into the binding mode of the SS-SAH, and further biological assays showed that this inhibitor can be turned off by changing the redox environment. This property provides the SSSAH structure with an interesting potential for use in in vitro enzymatic studies of functionally diverse methyltransferases.
Chapter 5 centers around the design and synthesis of bisubstrate mimics of human histidine methyltransferase SETD3. The synthesized compounds exhibited low inhibitory activity; however, these results provide information on the binding mode of the substrate and co-substate on the SETD3 binding site.
In Chapter 6, chemically diverse coenzyme A analogs were designed as inhibitors against human histone lysine acetyltransferases KAT8/MOF and KAT2A/GCN5, respectively, exploring different types of possible interactions with the co-substrate binding pocket. These coenzyme A analogs were synthesized in one step. The most potent inhibitor was ketone-substituted coenzyme A for both enzymes (IC50 = 10.9 μΜ for GCN5 and 13.6 μΜ for KAT8) and a general trend for carbonyl-substitution being beneficial for inhibition was observed.
Finally, in Chapter 7, dynamic combinatorial chemistry and kinetic target-guided synthesis methods were utilized for discovering coenzyme A-based inhibitors of GCN5, by using this enzyme as a template. Formation of thioether 4-methoxy-phanacetyl-CoA was observed to be kinetically favored and exhibited mild inhibitory activity (IC50 = 60.4 μΜ). We believe this method possesses significant potential for optimization and application as a strategy for targeted inhibition of lysine acetyltransferases.
Chapter 3 focuses on selected modifications on S-adenosyl-L-homocysteine for inhibition of human histidine methyltransferase SETD3, as well as histone lysine methyltransferases GLP, G9a and SETD8. We discovered that disruption of the hydrogen bond pattern in the N6-adenine moiety has a dramatic effect on the inhibition potency, however, selenated analogue SeAH was identified as a potent inhibitor for all screened enzymes, with IC50 values of 12.0 μM for SETD3, 116 nM for GLP, 1.8 μM for G9a and 452 nM for SETD8.
Chapter 4 covers the design and synthesis of a unique redox-labile S-adenosyl-L-homocysteine analog, SS-SAH, which possesses a disulfide bond. This compound showed inhibitory activity, with IC50 values of 30.4 μM for GLP, 95.4 μM for G9a and 4.4 μM for SETD8. Docking studies and biomolecular simulations provided insight into the binding mode of the SS-SAH, and further biological assays showed that this inhibitor can be turned off by changing the redox environment. This property provides the SSSAH structure with an interesting potential for use in in vitro enzymatic studies of functionally diverse methyltransferases.
Chapter 5 centers around the design and synthesis of bisubstrate mimics of human histidine methyltransferase SETD3. The synthesized compounds exhibited low inhibitory activity; however, these results provide information on the binding mode of the substrate and co-substate on the SETD3 binding site.
In Chapter 6, chemically diverse coenzyme A analogs were designed as inhibitors against human histone lysine acetyltransferases KAT8/MOF and KAT2A/GCN5, respectively, exploring different types of possible interactions with the co-substrate binding pocket. These coenzyme A analogs were synthesized in one step. The most potent inhibitor was ketone-substituted coenzyme A for both enzymes (IC50 = 10.9 μΜ for GCN5 and 13.6 μΜ for KAT8) and a general trend for carbonyl-substitution being beneficial for inhibition was observed.
Finally, in Chapter 7, dynamic combinatorial chemistry and kinetic target-guided synthesis methods were utilized for discovering coenzyme A-based inhibitors of GCN5, by using this enzyme as a template. Formation of thioether 4-methoxy-phanacetyl-CoA was observed to be kinetically favored and exhibited mild inhibitory activity (IC50 = 60.4 μΜ). We believe this method possesses significant potential for optimization and application as a strategy for targeted inhibition of lysine acetyltransferases.
Original language | English |
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Date of defence | 25. Jan 2024 |
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Publication status | Published - 14. Mar 2024 |