Design and synthesis of a novel fluorescent protein probe for easy and rapid electrophoretic gel staining by using a commonly available UV-based fluorescent imaging system.

A new fluorescent molecular probe, methyl 3-(3,5-bis((bis(pyridin-2-ylmethyl)amino)-methyl)-4-hydroxyphenyl)-2-(5-(dimethylamino)naphthalene-1-sulfonamido) propanoate, dizinc(II) chloride salt (Dansyl-1-Zn(II)), which possesses Zn(II) complexes and a dansyl group, was designed and synthesized to enable the detection of proteins in solution and in high-throughput electrophoresis by using a UV-based detection system. Dansyl-1-Zn(II) exhibited weak fluorescence in the absence of proteins and strong green fluorescence at approximately 510 nm in the presence of BSA upon irradiation with light at a wavelength of 345 nm. Compared with conventional protocols for in-gel SDS-PAGE protein staining (e.g. silver staining, SYPRO Ruby, and Oriole), the operating times of which range from 90 min to overnight, Dansyl-1-Zn(II) allowed 1-step protein staining (SDS-PAGE →Staining →Detection) and shortened the operating time (35 min) with high sensitivity (LOD: 1 ng or less) under 312-nm or 365-nm light excitation with orange or red emission filters, respectively. Moreover, Dansyl-1-Zn(II) was successfully applied to protein identification by MS via in-gel tryptic digestion, Western blotting, and Native-PAGE. Accordingly, Dansyl-1-Zn(II) may facilitate highly sensitive and high-throughput protein detection, and it may be widely applicable as a convenient tool in various scientific and medical fields.