Cost-Effective Production of ATP and S-Adenosylmethionine Using Engineered Multidomain Scaffold Proteins

Adenosine triphosphate (ATP) and S-adenosyl-L-methionine (SAM) are important intermediates that are widely present in living organisms. Large-scale preparation and application of ATP or SAM is limited by expensive raw materials. To lower the production costs for ATP/SAM, in this study we used strategies applying engineered multidomain scaffold proteins to synthesize ATP and SAM. An artificial scaffold protein containing CBM3 domain, IM proteins and CL-labeled proteins was assembled to form complex 1 for catalytic reactions to increase ATP production. The ATP synthesis system produced approximately 25 g/L of ATP with approximately 15 g/L of ADP and 5 g/L of AMP using 12.5 g/L of adenosine and 40 g/L of sodium hexametaphosphate reaction at 35 °C and a pH of 8.5 for 6 h. Based on the above ATP synthesis system, two CL-labeled methionine adenosyltransferases (CL9-MAT4 and CL9-MAT5) were applied to construct scaffold protein complex 2 to achieve SAM synthesis. Approximately 25 μg of MAT4 in a reaction system with 0.3 M MgCl₂ catalyzed at 20 °C and a pH of 8 catalyzed 0.5 g/L of l-Met to produce approximately 0.9 g/L of SAM. Approximately 25 μg of MAT5 in a reaction system with 0.7 M MgCl₂ catalyzed at 35 °C and a pH of 8 catalyzed 0.5 g/L of l-Met to produce approximately 1.2 g/L of SAM. Here, we showed that low-cost substrates can be efficiently converted into high-value additional ATP and SAM via multi-enzyme catalytic reactions by engineered multidomain scaffold proteins.