Sinteza in vrednotenje novih zaviralcev DNA-giraze B z N-(benzo[d]tiazol-2-il)-1H-pirol-2-karboksamidnim strukturnim delom

Fridrih, Nina (author), Zidar, Nace (mentor)

Odkritju večine pomembnejših skupin protibakterijskih učinkovin sredi 20. stoletja danes sledi zaskrbljujoča grožnja obdobja bakterijske odpornosti. Za premagovanje ovir pri razvoju nujno potrebnih novih protibakterijskih učinkovin znanstveniki raziskujejo nove molekularne tarče ali učinkovine, ki bi delovale na znane tarče preko novih mehanizmov delovanja. Ene izmed dobro uveljavljenih tarč so bakterijske topoizomeraze, kamor spadata tudi encima DNA-giraza in topoizomeraza IV. DNA-giraza in topoizomeraza IV imata pri podvajanju molekule DNA pomembno vlogo. Oba sta heterotetramerna encima, sestavljena iz dveh parov podenot: DNA-giraza iz dveh podenot GyrA in dveh podenot GyrB, topoizomeraza IV pa iz dveh podenot ParC in dveh podenot ParE. Podenoti GyrA in GyrB sta po aminokislinskem zaporedju podobni podenotam ParC in ParE. Zaradi strukturne podobnosti obstaja možnost načrtovanja učinkovin, ki zavirajo oba encima hkrati. Glavna funkcija GyrA/ParC je razcepitev in združitev molekule DNA med podvajanjem, energijo za ta proces pa zagotavlja GyrB/ParE s hidrolizo ATP. S pomočjo kristalnih struktur kompleksov DNA-giraze B z znanimi zaviralci smo načrtovali in pripravili 7 novih potencialnih ATP-kompetitivnih zaviralcev DNA-giraze B. Sintetiziranim spojinam je skupen N-(benzo[d]tiazol-2-il)-1H-pirol-2-karboksamidni del molekule. Spojine smo testirali na encimu DNA-giraza iz Escherichia coli, dve pa še na DNA-girazi bakterije Staphylococcus aureus ter na DNA topoizomerazi IV bakterije E. coli in S. aureus. Spojinam, ki so pokazale dobro aktivnost na encimih smo določili še protibakterijsko aktivnost na bakterijskih sevih Acinetobacter baumannii, E. coli, Enterobacter aerogenes, Enterococcus faecalis, Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa in S. aureus. Na encimskih in protibakterijskih testiranjih se je kot najbolj aktivna izkazala spojina 16, s srednjo zaviralno koncetracijo (IC50) 13,4 nM na DNA-girazo iz E. coli, ki ima v svoji strukturi 3,4-dikloro-5-metil-1H-pirolamidni fragment in prosto karboksilno kislino na desni strani molekule. Spojine 16 je imela zelo dobro aktivnost tudi na DNA-girazi iz S. aureus ter topoizomerazi IV iz E. coli in S. aureus, na protibakterijskem testiranju pa je dosegla zelo nizke minimalne zaviralne koncentracije (MIK90) proti bakterijam S. aureus (MIK90 = 1,56 µM), E. coli (MIK90 = 12,5 µM), E. faecalis (MIK90 = 0,39 µM), E. faecium (MIK90 = 0,56 µM) in A. baumannii (MIK90 = 6,25 µM).

• Language: Slovenian
• Keywords: protibakterijska učinkovina, ATP-kompetitivni zaviralci, DNA-giraza B
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2019
• PID: 20.500.12556/RUL-108339
• Publication date in RUL: 28.06.2019

Secondary language

• Language: English
• Title: Synthesis and evaluation of new DNA gyrase B inhibitors with the N-(benzo[d]thiazol-2-yl)-1H-pyrrole-2-carboxamide structural part

Abstract

The discovery of most major groups of antibacterial agents in the mid-20th century is now followed by an alarming threat of bacterial resistance period. In order to overcome the obstacles in the development of new antibacterial agents, scientists are exploring new molecular targets or agents that could act on the already known targets through new mechanisms of action. One of the well-established targets are bacterial topoisomerases DNA gyrase and topoisomerase IV. DNA gyrase and topoisomerase IV are enzymes that play an important role in replicating the DNA molecule. Both of them are heterotetrameric enzymes consisting of two pairs of subunits: DNA gyrase consists of two GyrA subunits and two GyrB subunits, and topoisomerase IV consists of two ParC subunits and two ParE subunits. The amino acid sequence in GyrA and GyrB subunits is similar as in ParC and ParE subunits. Due to the structural similarity, there is a possibility of designing active substances that inhibit both enzymes at the same time. The main function of GyrA/ParC subunit is cleavage and reunion of the DNA molecule during replication. The energy for this process is provided by the GyrB/ParE subunit through hydrolysis of ATP. With the use of known co-crystal structures of DNA gyrase B with known inhibitors, seven new potential ATP competitive DNA gyrase B inhibitors were designed and prepared. Synthesized compounds possess a common N-(benzo[d]thiazol-2-yl)-1H-pyrrol-2-carboxamide moiety. The compounds were tested on DNA gyrase from Escherichia coli, and two of them also on DNA gyrase from Staphylococcus aureus and on DNA topoisomerase IV from E. coli and S. aureus. Antibacterial activities on bacterial strains of Acinetobacter baumannii, Enterobacter aerogenes, E. coli, Enterococcus faecalis, Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa and S. aureus have been determined for compounds that exhibited good activity on enzymes. According to enzyme and antibacterial testing, compound 16, with a half-maximal inhibitory concentration (IC50) of 13.4 nM, was shown to be the most active on DNA gyrase from E. coli. It contains a 3,4-dichloro-5-methyl-1H-pyrrolamide fragment and a free carboxylic acid group on the right side of the molecule. Compound 16 also had a very good activity on DNA gyrase from S. aureus, and on topoisomerase IV from E. coli and S. aureus. It also showed low minimum inhibitory concentrations (MIC90) on S. aureus (MIC90 = 1.56 µM), E. coli (MIC90 = 12.5 ?M), E. faecalis (MIC90 = 0.39 ?M), E. faecium (MIC90 = 0.56 ?M) and A. baumannii (MIC90 = 6.25 ?M).

• Keywords: antibacterial drug, ATP-competitive inhibitor, DNA gyrase B