Key laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
National Engineering Research Center for Enzyme Technology in Medicine and Chemical Industry, Hunan Flag Bio-tech Co., Ltd., Changsha 410100, China.
J Agric Food Chem. 2024 Jul 31;72(30):16900-16910. doi: 10.1021/acs.jafc.4c03715. Epub 2024 Jul 17.
-Adenosylmethionine (SAM) is a crucial metabolic intermediate playing irreplaceable roles in organismal activities. However, the synthesis of SAM by methionine adenosyltransferase (MAT) is hindered by low conversion due to severe product inhibition. Herein structure-guided semirational engineering was conducted on MAT from (MAT) to mitigate the product inhibitory effect. Compared with the wild-type MAT, the best variant E56Q/Q105R exhibited an 8.13-fold increase in half maximal inhibitory concentration and a 4.46-fold increase in conversion (150 mM ATP and l-methionine), leading to a SAM titer of 47.02 g/L. Another variant, E56N/Q105R, showed superior thermostability with an impressive 85.30-fold increase in half-life (50 °C) value. Furthermore, molecular dynamics (MD) simulation results demonstrate that the alleviation in product inhibitory effect could be attributed to facilitated product release. This study offers molecular insights into the mitigated product inhibition, and provides valuable guidance for engineering MAT toward enhanced catalytic performance.
腺苷蛋氨酸（SAM）是一种重要的代谢中间产物，在生物活动中发挥着不可替代的作用。然而，由于产物抑制严重，蛋氨酸腺苷转移酶（MAT）合成 SAM 的转化率较低。本研究通过对 （MAT）进行基于结构的半理性工程改造，以减轻产物抑制效应。与野生型 MAT 相比，最佳变体 E56Q/Q105R 的半最大抑制浓度增加了 8.13 倍，转化率（150 mM ATP 和 L-蛋氨酸）增加了 4.46 倍，导致 SAM 产量达到 47.02 g/L。另一个变体 E56N/Q105R 具有出色的热稳定性，半衰期（50°C）值增加了 85.30 倍。此外，分子动力学（MD）模拟结果表明，产物抑制作用的减轻可能归因于产物释放的促进。本研究为减轻产物抑制提供了分子见解，并为工程化 MAT 以提高催化性能提供了有价值的指导。
