New Aspects of the Structure of d-Amino Acid Oxidase from Porcine Kidney in Solution: Molecular Dynamics Simulation and Photoinduced Electron Transfer

Mammalian d-amino acid oxidase (DAAO) plays an important role for d-serine metabolism in the brain and regulation of glutamatergic neurotransmission. In the present work, the structures in solution obtained by the methods of molecular dynamic simulation (MDS) and analyses of photoinduced electron transfer (ET) from aromatic amino acids to the excited isoalloxazine (Iso*) are described based upon our recent works, comparing among DAAO dimer, monomer, DAAO-benzoate (DAOB) complex dimer and monomer. The fluorescence lifetimes of DAAO and DAOB in the time domain of picoseconds and femtoseconds are used for the ET analyses as experimental data. The ET parameters (static dielectric constants near isoalloxazine (Iso), standard free energy gap (SFEG) between the photoproducts and reactants), ET rates, and related physical quantities (solvent reorganization energy, net electrostatic energy between the photoproducts and ionic groups in the proteins), in addition to MDS structures, are used to compare the protein structures. The structure of the DAOB dimer in solution obtained by MDS is substantially different from the crystal structure, and the structures of the two subunits are not equivalent in solution. The ET rates and related physical quantities also differ between the two subunits

Ultrafast carbonyl motion of the Photoactive Yellow Protein chromophore probed by femtosecond circular dichroism

International audienceMotions of the trans-p-coumaric acid carbonyl group following the photoexcitation of the R52Q mutant of Photoactive Yellow Protein (PYP) are investigated, for the first time, by ultrafast time-resolved circular dichroism (TRCD) spectroscopy. TRCD is monitored in the near ultraviolet, over a timescale of 10 ps. Immediately after excitation, TRCD is found to exhibit a large negative peak, which decays within a few picoseconds. A quantitative analysis of the signals shows that, upon excitation, the carbonyl group undergoes a fast (