Komatsu Teruyuki, Nakagawa Akito, Curry Stephen, Tsuchida Eishun, Murata Kenichi, Nakamura Nobuhumi, Ohno Hiroyuki
Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Org Biomol Chem. 2009 Sep 21;7(18):3836-41. doi: 10.1039/b909794e. Epub 2009 Jul 22.
Complexation of iron(II) protoporphyrin IX (Fe(2+)PP) into a genetically engineered heme pocket on recombinant human serum albumin (rHSA) creates an artificial hemoprotein which can bind O(2) reversibly at room temperature. Here we highlight a crucial role of a basic amino acid triad the entrance of the heme pocket in rHSA (Arg-114, His-146, Lys-190) for O(2) and CO binding to the prosthetic Fe(2+)PP group. Replacing His-146 and/or Lys-190 with Arg resolved the structured heterogeneity of the possible two complexing modes of the porphyrin and afforded a single O(2) and CO binding affinity. Resonance Raman spectra show only one geometry of the axial His coordination to the central ferrous ion of the Fe(2+)PP.
将亚铁原卟啉IX（Fe(2+)PP）络合到重组人血清白蛋白（rHSA）上经基因工程改造的血红素口袋中，可产生一种人工血红蛋白，它能在室温下可逆地结合O(2)。在此，我们强调了rHSA中血红素口袋入口处的一个碱性氨基酸三联体（Arg-114、His-146、Lys-190）对于O(2)和CO与辅基Fe(2+)PP基团结合的关键作用。用Arg取代His-146和/或Lys-190解决了卟啉可能的两种络合模式的结构异质性问题，并提供了单一的O(2)和CO结合亲和力。共振拉曼光谱显示轴向His与Fe(2+)PP中心亚铁离子配位只有一种几何结构。
