Structural Origin of the High Affinity of a Chemically Evolved Lanthanide‐Binding Peptide

Listening to Lanthanide Complexes: Determination of the Intrinsic Luminescence Quantum Yield by Nonradiative Relaxation

“…It can be seen that the higher quantum yield of the EuA C H T U N G T R E N N U N G (tta) 3 L 2 complex, in comparison with the EuA C H T U N G T R E N N U N G (bta) 3 L 2 complex, is not due to a higher energy transfer efficiency, but rather to the larger radiative rate and lower nonradiative rate. The values of f Ln are similar for terbium complexes, while h sens for TbA C H T U N G T R E N N U N G (bap) 3 ·4H 2 O is higher than that for Na 3 TbA C H T U N G T R E N N U N G (dpa) 3 ·NaCl·3H 2 O. The better ligand sensitization for TbA C H T U N G T R E N N U N G (bap) 3 ·4H 2 O may be understood by noting that there is a suitable energy gap (DE % 3000 cm À1 ) between the lowest triplet state of the ligand and the 5 D 4 state of terbiumA C H T U N G T R E N N U N G (III).…”

“…The better ligand sensitization for TbA C H T U N G T R E N N U N G (bap) 3 ·4H 2 O may be understood by noting that there is a suitable energy gap (DE % 3000 cm À1 ) between the lowest triplet state of the ligand and the 5 D 4 state of terbiumA C H T U N G T R E N N U N G (III). [48] For Na 3 TbA C H T U N G T R E N N U N G (dpa) 3 ·NaCl·3H 2 O this energy gap is large. [49] In Figure 5, it can be seen that h sens does not change much with temperature, while the intrinsic quantum yield of Eu 3 + decreases remarkably with increasing temperature.…”

“…When the energy difference between 3 T and L is very small, a backwards energy transfer from the excited state L to 3 T should be included in Figure 1. This backwards transfer from L to 3 T followed by nonradiative decay to the ground state, also belongs to the slow heat component, due to the continuous backwards energy transfer process from the long-lived excited state L.…”

“…These characteristics enable them to have wide application in responsive luminescent stains for biomedical analysis with temporal and spectral discrimination, [1][2][3][4][5][6][7][8][9] and to find use in development for liquid-crystal displays, [10][11][12][13] laser materials [14][15] and optoelectronic emitters. [16][17] Generally, the excellent luminescence properties of lanthanide complexes are attributed to the intramolecular energy transfer between the organic ligands and chelated metal ("antenna effect").…”

Site‐Specific Labelling of Proteins with a Rigid Lanthanide‐Binding Tag

“…Its sequence was based on the Ln 3 + -binding sequence YIDTNNDGWYEGDELLA, henceforth referred to as LBP1, which has been reported to bind Tb 3 + ions with 50 nm binding affinity [10] and for which a crystal structure has been determined. [11] The N-terminal cysteine residue was added to provide a site for attachment of LBP2 to a cysteine residue of the protein through a disulfide bond. The two C-terminal residues of LBP1 were omitted from LBP2, since NMR spectra recorded for the mutant peptide LBP1A C H T U N G T R E N N U N G (T4C) in complex with Lu 3 + ions showed that the C-terminal residues assumed two different slowly exchanging conformations, a fact suggesting This paper describes a generic method for the site-specific attachment of lanthanide complexes to proteins through a disulfide bond.…”