Formation of n → π⁺ interaction facilitating dissociative electron transfer in isolated tyrosine-containing molecular peptide radical cations

Abstract

Long-range electron transfers in proteins can be rationalized as a sequential short-distance electron-hopping processes via amino acid residues having low ionization energy as relay stations. Tyrosine residues can serve as...

Auf zur Wasserstoffentwicklung: Das Infrarot‐Spektrum von hydratisiertem Aluminiumhydrid‐Hydroxid HAlOH+(H2O)n−1, n=9–14

“…Quantenchemische Berechnungen auf dem B3LYP/6‐311++G**‐Theorieniveau wurden mit dem Softwarepaket Gaussian durchgeführt [20] . Die Infrarotspektren energetisch niedrig liegender Strukturen wurden durch Anwendung eines Skalierungsfaktors von 0,982 und einer Gaußschen Verbreiterung mit 20 cm −1 Halbwertsbreite auf die harmonischen Frequenzen simuliert [21] . Die Energien wurden auf dem M06/6‐311++G**‐Theorieniveau nach erneuter Geometrieoptimierung ausgewertet; während das M06‐Funktional dazu neigt, unrealistische Abweichungen der Absorptionsintensitäten vorherzusagen, [22] ist es dafür bekannt, dass es zuverlässigere Energien für wasserstoffgebundene Systeme liefert als B3LYP [23] .…”

Getting Ready for the Hydrogen Evolution Reaction: The Infrared Spectrum of Hydrated Aluminum Hydride–Hydroxide HAlOH+(H2O)n−1, n=9–14

“…Quantum chemical calculations at the B3LYP/6‐311++G** level of theory were performed using the Gaussian software package [20] . The infrared spectra of energetically low‐lying structures were simulated by applying a scaling factor of 0.982 and a Gaussian broadening with 20 cm −1 full‐width‐at‐half‐maximum to the harmonic frequencies [21] . Energies were evaluated at the M06/6‐311++G** level of theory after re‐optimization of the respective geometries; while the M06 functional may predict unrealistic variations of absorption intensities, [22] it is known to provide more reliable energies for hydrogen‐bonded systems than B3LYP [23] .…”

Control of Tyrosyl Radical Stabilization by {SiO2@Oligopeptide} Hybrid Biomimetic Materials

“…The local microenvironment determines the rate of oxidative Y • radical formation and stability via various factors: (i) covalent, hydrogen-bonding, ionic interactions between electron donor/electron acceptor ,,,, as well as the overall dipole moment of the tyrosine moiety; (ii) the distance between the electron donor and acceptor ,,, as well as the location of electron donor and acceptor, i.e., whether they are located in the same or different molecules; (iii) the dynamic properties of the surrounding protein, , including primary, secondary, and tertiary structures, as well as specific torsional peptide angles; , (iv) tyrosine exposure to a solvent , and the presence of metals; (v) the geometrical arrangement of the tyrosine moiety within each pocket: the orientation of the acetylated N-terminus, the alignment of the CO group and the amide bonds, , and the direction of the electron transfer pathway (N- to C- or C- to N-terminus). Finally, the liquid or solid phase also plays a critical role …”