Abstact

Klebsiella pneumonia acid phosphatase is widely employed in the large-scale synthesis of nucleotides. It was found that the phosphate acceptance capability of the substrate limited the efficiency of the phosphate transfer process. By reducing steric hindrance and optimizing substrate interaction with the catalytic site, variants of Klebsiella pneumonia acid phosphatase were designed, with the E104G variant showing significantly enhanced hydrolysis activity while maintaining high phosphorylation activity. Crystal structure and quantum mechanics/molecular mechanics analyses of the E104G variant revealed that the mutation promotes substrate binding and lowers the energy barrier. Based on these insights, several mutations were designed, achieving significantly improved conversion rates. By knocking out degradation-related enzymes, the degradation rates of inosinic acid and guanylic acid were successfully controlled. This study provides a structure-based top-down design strategy that effectively enhances enzyme specificity, offering a promising enzyme candidate for large-scale nucleotide synthesis.