Selective fluorescence sensing of biological thiols using a bodipy based bifunctional probe and the catalytic activity of short peptide amphiphile nanostructures : implications on the oring of life

Abstract

Chemosensor development is an attractive field of modern chemistry and there exist large amount of contribution from all over the world. The biological importance of thiols triggered the development of sensors to differentiate especially cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) which play key roles in biological systems. Concentration of those thiols results in number of diseases and their structural similarity complicates the differentiation. Optical probes especially fluorescent ones are widely employed for that purpose since it offers simplicity, sensitivity and low detection limits as well as real time analysis. BODIPY core is decorated with a Michael acceptor nitro-styrene group to covalent incorporation of thiols and with an aza-crown moiety to recognition of N-terminus of them. The work in this thesis is the first example in which one of them is separated from others or three of them separated from each other’s by chain length difference using fluorescence spectrometry. Formation of short peptides (2-4 aa residues) is considered to be likely under primordial conditions, following a number of scenarios. In this work, it is constructed a short peptide library limiting our choice of amino acids to those believed to be available at larger concentrations such as Gly, Ala, Asp and Cys. It is demonstrated that when acylated at the N-terminus, nanostructures of varying size and shapes were formed. Investigations on the catalytic activity of these nanostructures under different conditions are presented. The findings on the correlation of peptide structure and nanostructure formation and/or catalytic activity are presented.