Highly Selective Fluorescent Probe for Vicinal-Dithiol-Containing Proteins and In Situ Imaging in Living Cells

摘要

The protein thiol group is vulnerable to oxidation by reactive oxygen species and reactive nitrogen species, and plays a principal role in maintaining an appropriate oxidation-reduction state of the protein, regulating signal pathways and responding to various diseases such as cancer diabetes, and neurodegeneration. As the reductive end of this redox buffer network, vicinal-dithiol-containing proteins (VDPs) are attracting more and more attention. VDPs are proteins that contain two thiol groups that are close to each other in space. In fact, most contain the thiol groups as a -CX_nC- (n: normally 2-6, X: amino acid) motif instead of a CC sequence. In contrast to the situation when a single thiol group is present, the proximity of a second thiol group could promote immediate oxidation to form a disulfide following the transient intermediacy of an oxidative species, such as a sulfenic acid, a thiyl radical, or an S-nitrosothiol. Therefore, as one final end of the redox buffer network, protein vicinal dithiols show a higher tendency to cope with redox changes and are more sensitive and prone to free-radical oxidation.