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Photophysical properties and photochemical reactivity of tripeptides containing quinone methide precursors

Quinone methides (QMs) are reactive intermediates in the chemistry and photochemistry of phenols involved in a large number of chemical and biological processes such as enzyme inhibition, DNA alkylation and cross-linking [1]. Furthermore, it has been demonstrated that QMs exhibit antiproliferative activity, showing potential to be developed into anticancer drugs [2]. One strategy to enhance QMs reactivity with DNA and their antiproliferative activity is to bind the QM precursors to DNA intercallators [3]. We have recently demonstrated that modified tyrosine incorporated in oligopeptides can deliver QMs in the photochemical deamination reaction [3]. Herein we present photophysical properties and photochemical reactivity of tripeptide 1 that contains QM precursor - modified tyrosine and the TrpTrp dipeptide. The TrpTrpTyr sequence was chosen due to its known DNA binding ability [4], as well as fluorescent properties of Trp. Non- covalent and covalent binding of tripeptide 1 to DNA was assayed by fluorescence and CD titrations and by irradiations in the presence of DNA, respectively.

peptides ; tryptophan ; quinone methides ; photodeamination ; DNA binding

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