Common Motif at the Red Luminophore in Bovine Serum Albumin-, Ovalbumin-, Trypsin-, and Insulin-Gold Complexes

J Phys Chem Lett. 2021 Mar 25;12(11):2865-2870. doi: 10.1021/acs.jpclett.1c00222. Epub 2021 Mar 15.

Abstract

We examined the static and dynamic characters of the red luminescence in the protein-Au(III) compounds, directly comparing multiple proteins: BSA, OVA, trypsin, and insulin. These four protein-Au(III) complexes showed a nearly identical excitation-emission pattern, not only the wavelength of luminescence (λem ∼ 640 nm). Lifetimes of the red luminescence shared a common value of ∼300 ns. Kinetics of the luminophore formation was consistently described by a Langmuir-type chemisorption of Au(III) for these proteins, coinciding with the protein conformation change at pH ∼ 10. These observations and the protein structural analyses support that the red luminophore formation involves Au(III) coordination to a common motif within these proteins.

MeSH terms

  • Animals
  • Cattle
  • Coordination Complexes / chemistry*
  • Gold / chemistry*
  • Hydrogen-Ion Concentration
  • Insulin / chemistry*
  • Kinetics
  • Luminescent Measurements
  • Ovalbumin / chemistry*
  • Serum Albumin, Bovine / chemistry*
  • Trypsin / chemistry*

Substances

  • Coordination Complexes
  • Insulin
  • Serum Albumin, Bovine
  • Gold
  • Ovalbumin
  • Trypsin