Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy.
J Pept Sci. 2014 Jan;20(1):36-45. doi: 10.1002/psc.2586. Epub 2013 Nov 19.
A new metalloenzyme formed by a Fe(III)-mesoporphyrin IX functionalized by two helical decapeptides was synthesized to mimic function and structural features of a hemoprotein active site. Each decapeptide comprises six 2-aminoisobutyric acid residues, which constrain the peptide to attain a helical conformation, and three glutamic residues for improving the solubility of the catalyst in aqueous solutions. The new compound shows a marked amphiphilic character, featuring a polar outer surface and a hydrophobic inner cavity that hosts the reactants in a restrained environment where catalysis may occur. The catalytic activity of this synthetic mini-protein was tested with respect to the oxidation of L- and D-Dopa by hydrogen peroxide, showing moderate stereoselectivity. Structural information on the new catalyst and its adduct with the L- or D-Dopa substrate were obtained by the combined use of spectroscopic techniques and molecular mechanics calculations.
一种新型金属酶由两个螺旋十肽功能化的 Fe(III)-mesoporphyrin IX 组成，用于模拟血红素蛋白活性位点的功能和结构特征。每个十肽包含六个 2-氨基异丁酸残基，这些残基限制肽形成螺旋构象，并包含三个谷氨酸残基，以提高催化剂在水溶液中的溶解度。这种新化合物具有明显的两亲性特征，表面带极性，内部有空腔，可在受限环境中容纳反应物，从而可能发生催化作用。用该合成的小型蛋白进行了过氧化氢氧化 L-和 D-Dopa 的催化活性测试，表现出中等的立体选择性。通过光谱技术和分子力学计算的结合，获得了新型催化剂及其与 L-或 D-Dopa 底物的加合物的结构信息。
