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.