Study On The Interaction Of Perfluoroalkane Sulfonyl Fluorides On Nucleic Acids And Proteins

Perfluorinated and polyfluorinated substances are a class of very stable synthetic compounds,which are widely distributed in the natural environment.Previous studies have shown that these compounds have a variety of toxicities to human body.Currently,the research on the toxicity of perfluoroalkane sulfonyl fluorides（PFASFs）is still few.In this dissertation,we studied the interaction of PFOSF and its two short-chain analogues with nucleic acids and proteins,which may lay a foundation for further toxicity study in the future.This study mainly includes the following three parts:1.The reactivity of perfluoroalkane sulfonyl fluorides（PFASFs）with bases,nucleosides,deoxynucleosides,and nucleotides was investigated through electrospray ionization-mass spectrometry,and the collision induced dissociation of the products was analyzed.We found that PFASFs can react with bases,nucleosides,deoxynucleosides,and cyclic adenosine monophosphate.There are two types of reactions:one is sulfonylation with primary amines and the other is cyclization with hydroxyl groups of cytidine and uridine.The interaction between PFASFs and nucleotides was found to be non-covalent binding,and the affinity of PFASFs with double-stranded nucleotides is stronger than that with single-stranded nucleotides.2.The mechanism of the interaction of PFASFs with calf thymus DNA（ctDNA）was investigated through fluorescence spectroscopy using acridine orange（AO）as a fluorescent probe.Under the simulated physiological conditions,PFASFs quenched the fluorescence of AO-ctDNA.The quenching constant K_SVV decreases with increasing temperature and the quenching mode is static quenching.The binding constants of perfluorobutane sulfonyl fluoride（PFBSF）,perfluorohexane sulfonyl fluoride（PFHSF）and PFOSF with AO-ctDNA were determined to be 3.3×10^-3μM^-1,3.8×10^-3μM^-1,and3.77×10^-3μM^-1,respectively.The quenching effect of PFASFs on double-stranded DNA is greater than that on single-stranded DNA.The fluorescence intensity did not change too much when the ionic strength was changed.The interaction mode between PFASFs and ctDNA was found to be intercalation.3.The mechanism of the interaction of PFASFs with cytochrome c,lysozyme and myoglobin was investigated through electrospray ionization-mass spectrometry.The dissociation constants of the PFASF-protein complexes were determined by titration experiments.The results showed that PFASFs can form stable complexes with cytochrome c,lysozyme,and myoglobin at different molar concentration ratios,and the order of the stability of the three PFASF-protein complexes changes with the change of protein.