Studies towards the Developement of Small Molecule Inhibitors of Chorismate Synthase

The shikimate pathway plays a crucial role for the biosynthesis of aromatic amino acids, alkaloids and plant pigments, in prokaryotes, fungi and plants. The central metabolite chorismate is synthesized through seven enzymatic steps starting from erythrose-4-phosphate and phosphophenol pyruvate, which cannot be bypassed through any other enzyme. Therefore, inhibition of the shikimate pathway can lead to cell death, thus accounting for its toxicity against prokaryotes, fungi and plants. The fact, that the shikimate pathway is absent in mammals makes it a promising target for the development of antibiotics and fungicides. Recent investigations by Seixas and coworkers [1] using a combination of virtual screening and molecular dynamics revealed potent inhibitors for Paracoccidioides brasiliensis, which feature a naphthalene backbone. Recombinant in vitro and in vivo chorismate synthase binding to P. brasiliensis was confirmed for the identified hit compound. [1,2]

In this work we aim to take advantage of the previously identified hit compound in order to improve their affinity to chorismate synthase through structural modifications. Following this, we want to establish a structure-activity-relationship (SAR) around a certain chemotype and develop more affine compounds. Therefore, we synthesized first generation inhibitors with Kd values up to 19 µM. To further improve their affinity we want to develop a new second generation of small molecule inhibitors, which will also be tested in biological experiments (inhibition, binding, crystallization, in vitro, as well as cytotoxity studies), thus enabling to assess their pharmacological potential.

[1] Rodrigues-Vendramini F., Marschalk C., Toplak. M., Macheroux P., Bonfim-Nedoca P., Estivalet Svidzinski T., Seixas F., Kioshima E., Am. Soc. Microbiology, 2019, 63, 1.
[2] Bueno P., Toplak M. Macheroux P., Kioashima E., Seixas F., Future Microb., 2019, 14, 10.