Yu Yuehua, Chen Baowei, Qi Wen, Li Xiaolin, Shin Yongsoon, Lei Chenghong, Liu Jun
Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Microporous Mesoporous Mater. 2012 May 12;153:166-170. doi: 10.1016/j.micromeso.2011.12.005.
We report here a concept converting carbon dioxide to biocarbonate in a biomimetic nanoconfiguration. Carbonic anhydrase (CA), the fastest enzyme that can covert carbon dioxide to bicarbonate, can be spontaneously entrapped in carboxylic acid group-functionalized mesoporous silica (HOOC-FMS) with super-high loading density (up to 0.5 mg of protein/mg of FMS) in sharp contrast to normal porous silica. The binding of CA to HOOC-FMS resulted in a partial conformational change comparing to the enzyme free in solution, but it can be overcome with increased protein loading density. The higher the protein loading density, the less conformational change, hence the higher enzymatic activity and the higher enzyme immobilization efficiency (up to >60%). The released enzyme still displayed the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment, indicating that the conformational change resulted from the electrostatic interaction of CA with HOOC-FMS was not permanent. This work may provide a new approach converting carbon dioxide to biocarbonate that can be integrated with the other part of biosynthesis process for the assimilation of carbon dioxide.
我们在此报告一种在仿生纳米结构中将二氧化碳转化为碳酸氢盐的概念。碳酸酐酶（CA）是能够将二氧化碳转化为碳酸氢盐的最快的酶，它可以以超高负载密度（高达0.5毫克蛋白质/毫克FMS）自发地包埋在羧酸基团功能化的介孔二氧化硅（HOOC-FMS）中，这与普通多孔二氧化硅形成鲜明对比。与溶液中游离的酶相比，CA与HOOC-FMS的结合导致了部分构象变化，但随着蛋白质负载密度的增加，这种变化可以被克服。蛋白质负载密度越高，构象变化越小，因此酶活性越高，酶固定化效率也越高（高达>60%）。释放出的酶仍显示出天然的构象结构，并且具有与包埋前相同的高酶活性，这表明CA与HOOC-FMS的静电相互作用导致的构象变化不是永久性的。这项工作可能提供一种将二氧化碳转化为碳酸氢盐的新方法，该方法可与生物合成过程中用于二氧化碳同化的其他部分相结合。
