A quantum chemical study of the mechanism of tyrosinase

Article Abstract:

A study was conducted on the dicopper oxygenase called tyrosinase. Density function calculations were performed in two steps on a neutral model enzyme complex system L3Cu***CuL3 to examine the mechanism of the tyrosinase action. Ammonia ligands and, later in the experiment, formimine ligands, were used rather than histidine ligands. Among other results, a surprisingly strong bond of 23.2 kcal/mil between the two Cu(I)L3 monomers was formed using ammonia ligands.

Enzymes, Oxidases, Chemical systems

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Quantum chemical evidence for an intramolecular charge-transfer state in the caratenoid peridinin of peridinin-chlorophyll-protein

Article Abstract:

Quantum chemical evidence for a low-lying intramolecular charge-transfer (CT) state in peridinin using time-dependent density functional theory (TDDFT) with the Slator-Vosko Wilk-Nusair (SVWN) functional under the Tamm-Dancoff approximation. The energy of the CT state is shown to decrease dramatically in solvents of increasing polarity while the energy of the dark S1 (A(sub g)(super - )-like) state remains comparatively constant.

Methods, Analysis, Proteins, Charge transfer

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A quantum chemical approach to the study of reaction mechanisms of redox-active metalloenzymes

Article Abstract:

Hybrid density functional theory is used where full geometry optimizations are done with a medium basis and final energies are evaluated using much larger basis. Models consisting of 40-50 atoms containing the active site metal complex, including the first-shell amino acid ligands, are normally employed.

Metalloenzymes

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