Study of novel fluorophore-guanidine conjugates as ligands of human dipeptidyl-peptidase III combined experimental and computational approach

U ovom istraživanju ispitane su interkacije 7 novih konjugata gvanidiniokarbonilpirol (GCP)-fluorofora s humanom dipeptidil peptidazom III (DPP III) te je utvrđeno snažno vezanje svih spojeva u aktivno mjesto enzima, ali s vrlo različitim fluorimetrijskim odgovorom. Pozitivno nabijen lizinski bočni ogranak značajno je doprinio povećanju topljivosti spojeva i smanjenju jakosti fluorescentnog odgovora pri vezanju na DPP III, te potpuno ukinuo inhibitivni učinak na enzimsku aktivnost DPP III, dok su analozi s nenabijenom poveznicom pokazali snažniji porast emisije i učinkoviti su inhibitori enzima. Daleko najbolji fluorimetrijski odgovor i inhibitorna svojstva pokazao je analog GCP-cijanin, što ga čini dobrim sustavom za daljnje studije u kontekstu teragonstičkih primjena vezanih za humanu DPP III. U sklopu ove disertacije provedeno je istraživanje interakcija derivata GCP-pirena s dvolančanim DNA i RNA, pri čemu je ustanovljen visok afinitet vezanja i značajna razlika u fluorimetrijskim odgovorima, čime ti spojevi pokazuju svojstva dvostrukih senzora, koji omogućuju praćenje enzima DPP III te dvolančane DNA i RNA.Study of 7 new guanidiniocarbonylpyrrole (GCP)-fluorophore conjugates interactions with human dipeptidyl peptidase III (DPP III) showed that all compounds bind strongly to enzyme active site, but with very different fluorimetric response. Positively charged lysine side chain improved significantly compound solubility but diminished fluorescence increase upon DPP III binding and completely abolished inhibitor effect on DPP III activity, whereas linker-neutral analogues showed stronger emission increase and were efficient enzyme inhibitors. By far the best fluorimetric response and inhibitive properties showed cyanine-GCP analogue, thus being promising lead compound for both, enzyme sensing and bio-activity inhibiting (theragnostic) studies of human DPP III in the future. Study of pyrene-GCP derivatives interactions with double-stranded DNA and RNA, showed that all compounds have high binding affinity and significant difference in fluorimetric responses, thus showing properties of double sensors for DPP III and double-stranded DNA and RNA