Molecular Insight from DFT Computations and Kinetic Measurements into the Steric Factors Influencing Peptide Bond Hydrolysis Catalyzed by a Dimeric Zr(IV)-Substituted Keggin Type Polyoxometalate
作者:Tzvetan T. Mihaylov、Hong Giang T. Ly、Kristine Pierloot、Tatjana N. Parac-Vogt
DOI:10.1021/acs.inorgchem.6b01461
日期:2016.9.19
peptide bond hydrolysis, and (c) the influence of the aliphatic residues on the rate of hydrolysis. Formation of substrate–catalyst complexes of the dimeric POM 1 was predicted as thermodynamically unlikely. Instead, the substrates prefer to bind to the monomerization product of 1, [α-PW11O39Zr(OH)(H2O)]4– (2), which is also present in solution. In the hydrolytically active complex two dipeptide ligands
Zr(IV)取代的Keggin型多金属氧酸盐(POM)(Et 2 NH 2)催化的具有Gly-X序列(X = Gly,Ala,Val,Leu,Ile,Phe)的几种肽的肽键水解8 [α-PW 11 ø 39的Zr(μ-OH)(H 2 O)} 2 ]·7H 2 O(1),进行了研究的动力学实验和手段1个H NMR光谱。发现观察到的肽键水解速率随侧链体积的增加而降低,从Gly-Gly的4.44×10 –7 s –1降至0.81×10 –7 s –1对于Gly-Ile。进行了彻底的DFT研究,以阐明(a)溶液中水解活性物质的性质,(b)肽键水解的机理以及(c)脂族残基对水解速率的影响。预测形成二聚体POM 1的底物-催化剂复合物在热力学上不太可能。取而代之的是,底物更喜欢与1 [[-PW 11 O 39 Zr(OH)(H 2 O)] 4–(2)的单体化产物结合,该溶液也存在于溶液中。在具有水解