(A) novel artificial photosynthesis system based on bio-scaffolds

Abstract

Research to convert $CO_2$ to methanol using enzymes is a meaningful study from the two viewpoints of solving environmental pollution problems and producing useful chemicals. Nevertheless, there are limitations that the reducing activity of the enzymes is very low and the efficiency of three continuous enzymatic reactions is also not enough for industrial application. In this article, we measured the oxidation and reduction activity of enzymes obtained from various sources and determined appropriate candidates for the consecutive reaction. Then through mutant screening and in silico design method, we obtained mutants that reduction activity is increased or oxidation activity is decreased. Next, protein scaffold SNARE system was introduced to increase the efficiency of the continuous enzyme reaction and methanol production. SNARE fused WT enzymes increased the production of methanol 4.6 times more than free enzymes. Also, SNARE fused mutant enzymes with improved reduction activity and SNARE fused mutant enzymes without oxidation activity increased 13.5 and 15.8 times more than free enzymes, respectively. We developed in vivo screening systems for mutant screening and obtained reductivity improved enzymes using the systems. Also, we introduced SNARE module to protein scaffold system at the first time. They can be useful background for artificial photosynthesis research which produces methanol using $CO_2$.