Binding of Lanthanide Complexes to Histidine‐Containing Peptides Probed by Raman Optical Activity Spectroscopy

Abstract

Lanthanide complexes are used as convenient spectroscopic probes for many biomolecules. Their binding to proteins is believed to be enhanced by the presence of histidine, but the strength of the interaction significantly varies across different systems. To understand the role of peptide length and sequence, short histidine-containing peptides have been synthesized (His-Gly, His-Gly-Gly, His-Gly-Gly-Gly, Gly-His, Gly-His-Gly, His-His, and Gly-Gly-His) and circularly polarized luminescence (CPL) induced at the [Eu(dpa) ] complex has been measured by means of a Raman optical activity (ROA) spectrometer. The obtained data indicate relatively weak binding of the histidine residue to the complex, with a strong participation of other parts of the peptide. Longer peptides, low pH, and a histidine residue close to the N-peptide terminus favor the binding. The binding strengths are approximately proportional to the CPL intensity and roughly correlate with predictions based on molecular dynamics (MD) simulations. The specificity of lanthanide binding to the peptide structure and its intense luminescence and high optical activity make the ROA/CPL technique suitable for probing secondary and tertiary structures of peptides and proteins.

Binuclear Lanthanide(III) Complexes with Chiral Ligands: Dynamic Equilibria in Solution and Binding with Nucleotides Studied by Spectroscopic Methods

“…Particularly intense are the 5 D 0 → 7 F 0 and 5 D 0 → 7 F 1 europium transitions. Recently, we used the CPL/ROA technique for lanthanide‐based sensing of biomolecules such as amino acids and proteins, oligopeptides, saccharides, and nucleic acids …”

Resonance Raman Optical Activity Shows Unusual Structural Sensitivity for Systems in Resonance with Multiple Excited States: Vitamin B12 Case

“…http://doc.rero.chPublished in "The Journal of Physical Chemistry Letters 11(13): 5037-5043, 2020" which should be cited to refer to this work.…”

Induced Lanthanide Circularly Polarized Luminescence as a Probe of Protein Fibrils

“…Within the 5 D 0 → 7 F 1 transition region, negative (592 nm) and positive (594 nm) bands appear for l -PGA, with maximum CID of 1.1 × 10 –2 indicating a strong binding between the peptide and Eu 3+ . 23 Weaker bands are apparent at 579 and around 555 nm. d - and l -PGA provide approximately “mirror image” CPL spectra; although the magnitudes are slightly different and the d -PGA fibrils grew much faster than those of l -PGA (cf.…”

“…In the past, lanthanide CPL has been applied to amino acids, peptides, and saccharides, but application for fibrils is not known to us. 23−25 On the other hand, “conventional” CPL of the thioflavin T (ThT) dye absorbed on insulin fibrils did provide encouraging results. 26 Unlike the organic dyes, lanthanides provide more numerous and sharper bands, and hence potentially more information about studied systems.…”