The level of acetylation of mitochondrial proteins can serve as a signature index for diagnosing important metabolic diseases. The presented study describes the development of a convenient probe employing CuInS2/ZnS quantum dots (CIS QDs) for real-time monitoring the level of acetylation in living cells. The design of this nanoscale probe is based on electrostatically mediated quenching of the photoluminescence (PL) of QDs. (See the attached figure.) The CIS QDs are capped with peptide substrates which are capable of carrying out acetylation and deacetylation reactions, similar to their counterparts in mitochondria. The acetylation/deacetylation reactions vary the density of positive charges on the QD surface. A positively charged electron acceptor, methyl viologen (MV2+), is conjugated to the nanoparticle through a flexible poly (ethylene glycol) chain. The electrostatic interaction between the MV2+ quencher and the QD surface mediates the separation distance, which governs the quenching of the QD PL through the electron transfer process. The change of the PL intensity hence reports the degree of acetylation of the peptides presented by the QD probe. Time-resolved optical spectroscopic experiments measure the kinetic parameters of the distance-dependent electron transfer process, and help the optimization of this nanoscale probe.

CuInS2/ZnS quantum dot based probe for monitoring the acetylation of mitochondrial proteins

255th National Meeting (2018)

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