Sinteza tiazolnih zaviralcev ligaze MurA in monoamin oksidaz

Demšar, Lucija (author), Frlan, Rok (mentor)

Odpornost bakterij je eden od glavnih javnozdravstvenih problemov. Medtem ko imamo v klinični uporabi že veliko spojin, ki protibakterijski učinek dosežejo tako, da zavirajo gradnjo peptidoglikana v kasnejših stopnjah sinteze, so začetni koraki sinteze še neizkoriščene tarče. Eden od teh encimov je ligaza MurA, ki katalizira prvi korak sinteze peptidoglikana. Monoamin oksidaza (MAO) je mitohondrijski encim, ki katalizira oksidativno deaminacijo monoaminov. V telesu se nahaja v dveh izooblikah, MAO-A in MAO-B, ki se razlikujeta v strukturi aktivnih mest in v substratih, ki jih razgrajujeta. V klinični uporabi je že več zaviralcev, ki se razlikujejo v selektivnosti in se uporabljajo v terapiji Parkinsonove, Alzheimerjeve in drugih nevrodegenerativnih bolezni. V okviru magistrske naloge smo uspešno sintetizirali osem spojin, ki predstavljajo analoga dveh tiazolov, ki sta imela pri predhodnem testiranju knjižnice kovalentnih fragmentov zaviralno aktivnost na MurA. Spojine so se razlikovale v substituentih, vezanih na tiazolni obroč. Pri večini sinteznih postopkov smo namesto običajnega segrevanja uporabili obsevanje z mikrovalovi. Sintezni postopki so vključevali elektrofilne in nukleofilne aromatske substitucije, Suzukijevo in Stilleovo pripajanje ter Rosenmund-von Braunovo sintezo. Predhodno sintetizirana spojina zadetek se je v encimu MurA vezala na cistein v aktivnem mestu. Ker ima encim MAO prav tako cistein v aktivnem mestu, smo uspešno sintetizirane spojine poleg ligaze MurA testirali še na humanih encimih MAO-A in MAO-B. Najmočnejše zaviralno delovanje na ligazo MurA kaže spojina, ki ima na tiazolni obroč vezan brom in piridinsko skupino. Spojina, ki ima na obroč vezano karbonitrilno in dimetilaminsko skupino, je najuspešnejša pri neselektivnem zaviranju obeh izooblik encima MAO. Najmočnejše selektivno delovanje na encim MAO-B kažeta spojini, ki imata vezano fenilno skupino na tiazolni obroč na mestu 2. Tekom dela smo preučili vpliv različnih substituentov na tiazolnem obroču na zaviranje encimov ligaza MurA in obeh izooblik monoamin oksidaze ter pridobili spojine, ki bodo izhodišče za nadaljnji razvoj tiazolov kot potencialnih zdravilnih učinkovin.

• Language: Slovenian
• Keywords: ligaze Mur, MAO, protibakterijske učinkovine, nevrodegenerativne bolezni, tiazoli
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2020
• PID: 20.500.12556/RUL-116107
• Publication date in RUL: 15.05.2020

Secondary language

• Language: English
• Title: Synthesis of thiazole-based MurA ligase and monoamine oxidase inhibitors

Abstract

Bacterial resistance is one of the major world health problems. While there are already many compounds in clinical use that work by inhibiting peptidoglycan synthesis in subsequent steps, the initial steps of the synthesis pathway are still unexploited targets. One of these enzymes is MurA ligase, which catalyzes the first step of the peptidoglycan synthesis pathway. Monoamine oxidase (MAO) is a mitochondrial enzyme that catalyzes the oxidative deamination of monoamines. In the body, it is present in two isoforms, MAO-A and MAO-B, which are different in the structure of active sites and substrates that they degrade. There are already several inhibitors in clinical use that differ in selectivity and are used in treatments of Parkinson’s, Alzheimer´s and other neurodegenerative diseases. In this master´s thesis, we successfully synthesized eight compounds, which are analogs of two thiazoles that showed inhibitory activity on MurA when the library of covalent fragments was tested. The compounds differ in substituents bound to the thiazole ring. Microwave irradiation was used for most synthesis procedures instead of regular heating. The synthesis reactions included electrophilic and nucleophilic aromatic substitutions, Rosenmund-von Braun reaction, Suzuki and Stille coupling. The previously synthesized hit compounds bounded to cysteine in the active site of enzyme MurA. Because the enzyme MAO also has cysteine in the active site, the successfully synthesized compounds were tested for inhibitory activity of MurA ligase, human MAO-A and MAO-B. The strongest inhibition of MurA ligase is shown by the compound, which has a bromine and pyridine group attached. Compound with carbonitrile and dimethylamine group attached to the ring is the most successful non-selective MAO inhibitor. The strongest selective MAO-B inhibition is shown by the compounds, which both have a phenyl group attached to the thiazoles ring. We studied the effect of different thiazole ring substituents on inhibition of MurA ligase and both monoamine oxidase isoforms. Obtained compounds will represent basis for further development of thiazole-based compounds as potential active substances.

• Keywords: Mur ligases, MAO, antibacterial agents, neurodegenerative diseases, thiazoles