Effects of protein association on the rates of photoinduced electron transfer from tryptophan residues to excited flavin in medium-chain acyl-Co A dehydrogenase. Molecular dynamics simulation
Effects of protein association on the rates of photoinduced electron transfer from tryptophan residues to excited flavin in medium-chain acyl-Co A dehydrogenase. Molecular dynamics simulation
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DOI：
10.1016/j.jphotochem.2020.113039
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发表时间：
2021-02-15
影响因子：
4.3
通讯作者：
Chosrowjan, Haik
中科院分区：
文献类型：
--
作者：
Lugsanangarm, Kiattisak;Tanaka, Fumio;Chosrowjan, Haik
利用分子动力学模拟（MDS）得到的中链酰基辅酶A脱氢酶（MCAD）的完整四聚体结构和实验报道的超快荧光衰减，研究了MCAD中黄素腺嘌呤二核苷酸（FAD）的色氨酸残基（Trps）到受激异咯嗪（Iso*）的光诱导电子转移（ET）速率.在4种Trp中，Trp 166 ~ Iso* 的ET速率最快。通过引入Iso* 的发射波长依赖的电子亲合势，阐明了发射波长依赖的衰变。亚基C的ET速率比其他亚基慢得多，这归因于亚基之间的非等效静电相互作用。比较了四聚体和单体中蛋白质缔合对ET速率和相关物理量的影响。四聚体中的给体-受体距离比单体中的短。Trp 166在四聚体中的ET速率比在单体中慢。在七个发射波长下检查ET率和相关物理量。在所有亚基上，光产物与反应物之间的标准自由能隙随发射波长的增大而增大。随着发射波长变长，Sub A、Sub C和Sub D的ET率显示降低。
Rates of photoinduced electron transfer (ET) from tryptophan residues (Trps) to excited isoalloxazine (Iso*) of flavin adenine dinucleotide (FAD) in medium-chain acyl Co A dehydrogenase from porcine kidney (MCAD) have been studied using its entire tetrameric structures obtained by molecular dynamics simulation (MDS) and experimental ultrafast fluorescence decays reported. The ET rates were fastest from Trp166 to Iso* among the four Trps. The emission-wavelength dependent decays were elucidated by introducing emission-wavelength dependent electron affinity of Iso*. The ET rates in Sub C were much slower than those in other subunits, which was ascribed to non-equivalent electrostatic interactions among the subunits. Effect of the protein association on the ET rates and related physical quantities were examined comparing those in the tetramer and monomer reported. The donor-acceptor distances in the tetramer were shorter than those in the monomer. The ET rates from Trp166 in the tetramer were slower than that in the monomer. The ET rates and related physical quantities were examined at seven emission wavelengths. The values of standard free energy gap between the photo-products and reactants displayed to increase as the emission wavelength becomes longer at all subunits. The ET rates displayed to decrease in Sub A, Sub C and Sub D, as the emission wavelength becomes longer.