Related Experiment Video
Updated: May 5, 2026

Fluorescence Anisotropy as a Tool to Study Protein-protein Interactions
Published on: October 21, 2016
A possible calcium binding site in D1 protein: A fluorescence and FTIR study of the interaction between lanthanides
1National Laboratory of Applied Organic Chemistry, Lanzhou University, 730000, Lanzhou, P.R. China.
Abstract:
A peptide ranging from residue 229 to 240 of the D1 protein of Photosystem (PS) II was synthesized and lanthanides were used as candidates of calcium. Fluorescence and FTIR spectroscopy were used to test the conformational adaptation after lanthanide additions. Fluorescence spectroscopy showed that the synthetic peptide provides lanthanide binding site, and that glutamic acids are involved in lanthanide binding. Resolution enhancement techniques were combined with band curve-fitting procedures to quantitate the FTIR spectral information from the amide 1 bands. The relative areas of these component bands indicate that lanthanide induced a substantial decrease in the amount of unordered structure and turns, while a corresponding increase in the amount of α-helix and 'open loop' was also observed. This indicates that a relatively compact structure of the synthetic peptide is formed if lanthanides are applied. The results may reflect on the physiological and biochemical function of calcium in PS II, including preventing D1 from trypsin digestion.
Related Concept Videos
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Ligand Binding and Linkage

