Alen Kužat (Author), Tihomir Tomašić (Mentor)

Abstract

Živimo v času, ko bakterijska rezistenca na protibakterijske učinkovine predstavlja vedno večjo težavo. Zato je potrebno razvijati učinkovine, proti katerim bi bakterije postale težje odporne. Smiselno je torej odkrivati učinkovine, ki bi imele v mikroorganizmih nove tarče, ali pa iste tarče, vendar bi nanje delovale z drugačnim mehanizmom delovanja. Bakterijska DNA-giraza in topoizomeraza IV sta esencialna bakterijska encima, ki nadzorujeta topološko stanje molekule DNA med replikacijo. Oba encima sta že uveljavljeni tarči protibakterijskih učinkovin. Ključni vir energije za delovanje obeh encimov predstavlja molekula ATP. V magistrski nalogi bomo podrobneje predstavili sintezo novih pirolamidnih zaviralcev DNA-giraze in topoizomeraze IV. Zaviralci so bili načrtovani tako, da se vežejo v ATP-vezavno mesto na encimu. Pirolni fragment zaviralcev naj bi oponašal adeninski del molekule ATP. Hkrati smo na pirol vezali tudi elektron-privlačne skupine, s čimer smo izboljšali interakcije v vezavnem mestu. Na zaviralce smo vezali tudi različne stranske verige, s čimer smo preučevali, kako to vpliva na samo vezavo molekule. Končnim spojinam smo sprva določili rezidualno aktivnost na izoliranem encimu pri koncentraciji 100 μM, in če je bila rezidualna aktivnost encima manjša od 50%, smo tem spojinam nadalje določili še vrednosti IC50 na izoliranih encimih DNA-girazi in topoizomerazi IV iz bakterijskih sevov Escherichia coli in Staphylococcus aureus. Največjo zaviralno aktivnost na izolirani DNA-girazi iz bakterije E. coli je izkazala spojina 11 z IC50=0,0418 μM. Spojine so bile testirane tudi za protibakterijsko aktivnost na dveh po Gramu pozitivnih (Enterococcus faecalis in S. aureus) in dveh po Gramu negativnih (E. coli in Pseudomonas aeruginosa) bakterijskih sevih. Od vseh spojin je samo spojina 12 izkazovala protibakterijsko aktivnost na bakterijskih sevih E. faecalis in S. aureus pri MIC=50 μM.

Keywords

zaviralci DNA giraze;topoizomeraza IV;protibakterijske učinkovine;prokarionti;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FFA - Faculty of Pharmacy
Publisher: [A. Kužat]
UDC: 615.015.8(043.3)
COBISS: 4111473 Link will open in a new window
Views: 916
Downloads: 248
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Synthesis of 3,4-diclhloro-5-methyl-1H-pyrrole-2-carboxamide-based inhibitors of DNA-gyrase and topoisomerase IV
Secondary abstract: Nowadays bacterial resistance represents an increasing problem, since the existing drugs are no more that effective towards resistant bacteria. Therefore, it is necessary to discover drugs, against which bacteria would develop resistance more difficult. It makes sense to discover drugs acting on new targets in microorganism or targeting known targets, but with a different mode of action. Bacterial DNA gyrase and topoisomerase IV are essential enzymes that control the topological state of DNA during replication and are validated antibacterial drug targets. The source of energy for both enzymes represents the ATP molecule. In this Master's thesis we will present the synthesis of novel pyrrolamide-based inhibitors of DNA gyrase and topoisomerase IV. Inhibitors were designed in a way to bind into the ATP-binding site. The pyrrole fragment mimics the adenine part of the ATP molecule. We have also attached electron withdrawing groups on the pyrrol moiety to achieve better interactions in the binding, introduced different side chains and studied structure-activty relationship. Final compounds were also tested for their enzyme inhibitory activity at 100 μM. If the residual activity of the enzyme was lower than 50%, we determined also the IC50 values on isolated enzymes DNA gyrase and topoisomerase IV from bacterial strains Escherichia coli and Staphylococcus aureus. The most potent compound on the isolated DNA gyrase from E. coli was compound 11 with an IC50value of 0,0418 μM. The compounds were also tested for antibacterial activity on two Gram positive (Enterococcus faecalis in S. aureus) and two Gram negative (E. coli in Pseudomonas aeruginosa) bacterial strains. Among all compounds only compound 12 showed activity against E. faecalis and S. aureus bacterial strains at MIC=50 μM.
Secondary keywords: Bakterijska rezistenca;
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. Ljubljana, Fak. za farmacijo
Pages: VIII, 51 f.
ID: 12048488