Biokemijska analiza reaktivacije fosfilirane butirilkolinesteraze u ovisnosti o strukturi oksima

doctoral thesis

• Title (english): Biochemical analysis of the reactivation of phosphylated butyrylcholinesterase in relation with the oxime structure
• Author: Tena Čadež
• Mentor: Zrinka Kovarik (mentor)
• Committee member: Ines Primožič (predsjednik povjerenstva)
• Committee member: Jasmina Rokov Plavec (član povjerenstva)
• Committee member: Ivana Radojčić Redovniković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-12-21, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Sposobnost butirilkolinesteraze (BChE) da vezanjem organofosfornih (OP) spojeva snižava njihovu koncentraciju u organizmu i time sprječava inhibiciju acetilkolinesteraze (AChE) predstavlja novi temelj terapije kod otrovanja ovim spojevima. Budući da za reaktivaciju BChE još uvijek nije pronađen učinkovit oksim, cilj ovog istraživanja bio je ispitati učinkovitost i strukturne karakteristike dvaju različitih skupina oksima u reaktivaciji BChE fosfilirane različitim organofosfatima koristeći in silico i in vitro pristup. Od 123 spojeva 1-heksil-2-((hidroksiimino)metil) piridinijev oksim pokazao se najučinkovitijim reaktivatorom fosfilirane BChE, posebice u slučaju inhibicije ciklosarinom. Molekulskim modeliranjem pokazano je njegovo povoljno pozicioniranje u blizini fosfoniliranog katalitičkog serina uz stabilizaciju hidrofobnim interakcijama s Trp82 što omogućuje brzu nukleofilnu supstituciju fosfilne skupine s serina. Pseudokatalitički par ovog oksima i BChE u ex vivo uvjetima razgradio je stostruki suvišak ciklosarina uz povrat 70 % katalitičke aktivnosti kolinesteraza unutar 2 minute. Zaključno, pentil/heksil-temeljeni monopiridinijevi oksimi pokazali su se kao perspektivni strukturni motiv za daljnji razvoj oksima i terapije u kojoj bi učinkoviti reaktivatori s BChE omogućavali pseudokatalitičku degradaciju OP toksina u krvi.

Abstract (english)

The ability of butyrylcholinesterase (BChE) to bind organophosphorus (OP) compounds lowering their concentration in the body and preventing the inhibition of acetylcholinesterase (AChE) represents a new basis for therapy in OP poisoning. Since no effective oxime has yet been found for the reactivation of BChE, the aim of this research was to examine efficiency and structural characteristics of two different oxime groups in the reactivation of BChE phosphorylated with different organophosphates using in silico and in vitro approaches. Out of 123 compounds, 1-hexyl-2-((hydroxyimino)methyl) pyridinium oxime proved to be the most effective reactivator of phosphorylated BChE, especially in the case of cyclosarin inhibition. Molecular modeling showed its favorable positioning near the phosphonylated catalytic serine stabilized by hydrophobic interactions with Trp82, which enables rapid nucleophilic substitution of the phosphyl group from serine. Pseudocatalytic pair of this oxime and BChE in ex vivo conditions degraded a hundredfold excess of cyclosarin with 70 % recovery of cholinesterase catalytic activity within 2 minutes. In conclusion, pentyl/hexyl-based monopyridinium oximes proved to be a promising structural motif for further development of oximes and therapy in which effective BChE reactivators would enable pseudocatalytic degradation of OP toxins in the blood.

• Keywords: biološka čistila; kolinesteraze; molekulsko modeliranje; organofosforni pesticidi; reaktivatori; živčani bojni otrovi
• Keywords (english): bioscavengers; cholinesterases; molecular modelling; nerve agents; organophosphorus pesticides; reactivators
• Language: croatian
• URN:NBN: urn:nbn:hr:217:275859
• Promotion: 2023
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 151 str. ; 30 cm
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2024-12-21
• Created on: 2023-02-01 09:46:53