Monitoring intracellular metal ion complexation with an acetylene-tagged ligand by Raman spectroscopy. Issue 59 (1st October 2020)

• Record Type: Journal Article
• Authors: Takemura, Seiya; Watanabe, Hikaru; Nishihara, Tatsuya; Okamoto, Akimitsu; Tanabe, Kazuhito
• Is Part Of: RSC advances. Volume 10:Issue 59(2020)
• Page Start: 36119
• Page End: 36123
• Publication Date: 2020-10-01
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra06329k
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Complexation between acetylene-tagged ligand and Zn 2+ cations was tracked by monitoring changes in molecular vibration. Abstract : We propose to monitor molecular vibrations to identify metal ion–ligand complexation by means of Raman spectroscopy, which has been applied to track vibrational modes of molecules and to obtain a structural fingerprint. We prepared ligand molecules for Zn 2+ ion complexation with a dipycolylaminoethyl aniline (DPEA) skeleton and phenylacetylene unit as the Raman tag which showed a typical band around 2200 cm −1 . Among the labeled ligands synthesized in this study, A-DPEA showed a strong band attributed to the acetylene unit at 2212 cm −1, while the addition of Zn 2+ ion resulted in a band shift to 2220 cm −1 due to complex formation. The addition of other metal ions and titration experiments showed that A-DPEA bound with Zn 2+ selectively with a dissociation constant ( K d ) that was estimated to be 0.22 μM. We also conducted cellular experiments and found that complexation between A-DPEA and Zn 2+ also occurred in cells, with a shift in the Raman signal of the ligand from 2212 to 2215 cm −1 . Thus, complex formation of the metal ion was identified by monitoring the Raman band shift.