20.500.12556/DKUM-90121 Preučevanje interakcij med tanini in lizocimom diplomsko delo univerzitetnega študijskega programa I. stopnje Elucidation of tannin-lysozyme interactions Razvoj odpornosti bakterij na antibiotike je eden izmed večjih izzivov človeštva, ki zahtevajo tako iskanje novih protibakterijskih učinkovin, kot tudi izboljšanih načinov uporabe protibakterijskih sredstev. Raziskovalci nove protibakterijske učinkovine iščejo tudi med naravnimi spojinami s protimikrobnimi in protibakterijskimi učinki. Rastline vsebujejo tanine, ki so polifenolni sekundarni metaboliti, ki jih raziskujemo zaradi njihovih številnih potencialnih za zdravje ugodnih učinkov. Glede na njihovo kemijsko strukturo jih delimo na proantocianidine (kondenzirane tanine) in hidrolizirajoče tanine. Slednji se nadalje razdelijo na dve glavni podskupini (galotanin in elagitanini). V diplomskem delu smo proučevali vezavo elagitaninov na lizocim – modelni protein. Po dializi v pufru s pH = 5 smo lizocim titrirali z galno kislino, metil galatom in veskalaginom. Opazovali smo, kako prisotnost elagitaninov vpliva na fluorescenco lizocima. Vpliv dodatka taninov na sekundarno strukturo lizocima smo opazovali s cirkularnim dikroizmom (CD-spektroskopija), medtem ko smo termodinamiko vezave opazovali z izotermno titracijsko kalorimetrijo (ITC). Z opazovanjem temperaturne odvisnosti fluorescenčnega spektra lizocima smo ugotovili, da prisotnost taninov ne vpliva na temperaturo tališča proteina. S pomočjo Stern-Volmerjeve enačbe ob upoštevanju učinka notranjega filtra smo poskusili pridobiti konstante vezave taninov na lizocim. S CD-spektroskopijo smo ugotovili, da ima veskalagin večji vpliv na denaturacijo proteina, kot metil galat in galna kislina. Ugotovili smo, da je interakcija veskalagina in lizocima mnogo bolj eksotermna, kot interakcija metil galata ali galne kisline z lizocimom. Poleg tega smo z ITC-jem potrdili, da gre pri interakcijah taninov z lizocimom za razmeroma šibke interakcije. The emergence of bacterial antibiotic resistance is a critical challenge facing modern medicine, necessitating the discovery of novel antibacterial agents and the optimization of existing antibacterial strategies. Researchers increasingly use natural compounds with antimicrobial and antibacterial properties as potential solutions. Among these, plants represent a prime source of tannins, which are polyphenolic secondary metabolites being studied for their wide-range of health benefits. Tannins are categorized based on their chemical structures into two primary groups: proanthocyanidins (condensed tannins) and hydrolysable tannins. Hydrolysable tannins are further divided into two main subgroups: gallotannins and ellagitannins. In this thesis, we investigated the binding interactions between ellagitannins and lysozyme, a model protein. After dialysis in a pH 5.5 buffer, lysozyme was titrated with gallic acid, methyl gallate, and vescalagin. We monitored the effects of ellagitannins on the fluorescence of lysozyme, as well as changes in the protein's secondary structure using circular dichroism (CD spectroscopy). The thermodynamics of resulting interactions were assessed via isothermal titration calorimetry (ITC). By analyzing the temperature dependence of lysozyme’s fluorescence spectrum, we determined that the presence of tannins did not alter the protein’s melting temperature. Using the Stern-Volmer equation and accounting for the internal filter effect, we estimated the binding constants of tannins to lysozyme. Our CD spectroscopy results revealed that vescalagin has a greater impact on protein denaturation compared to methyl gallate and gallic acid. ITC analysis further showed that the interaction between vescalagin and lysozyme is significantly more exothermic than the interactions with methyl gallate or gallic acid. However, the interactions of tannins with lysozyme are still relatively weak. elagitanini protein konstanta vezave sekundarna struktura spektroskopija termodinamični parametri vezave tannins protein binding constant secondary structure spectroscopy thermodynamic binding parameters true true false [A. Zaverla] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2024-08-22 23:57:26 2024-09-17 14:33:40 2024-12-24 03:09:28 0000-00-00 00:00:00 2024 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (IX, 49 f.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 [544:536-1]:547.98(043.2) 220279043 UN_Zaverla_Anja_2024.pdf UN_Zaverla_Anja_2024.pdf 1 E2E512053FAB91A7A6E749C9B42DFD60 042f5cfd082cd212a923ad415a223440519bfafa7b2c34ea999dd4b0f19fcc00 ba256a6c-74d4-11ef-8b85-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=185295 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0