Engineering a Feruloyl–Coenzyme A Synthase for Bioconversion of Phenylpropanoid Acids into High-Value Aromatic Aldehydes
Qihang Chen, Yaqin Jiang, Zhengzhong Kang, Jie Cheng, Xiaochao Xiong, Ching Yuan Hu, Yonghong Meng
Abstract
Aromatic aldehydes find extensive applications in food, perfume, pharmaceutical, and chemical industries. However, a limited natural enzyme selectivity has become the bottleneck of bioconversion of aromatic aldehydes from natural phenylpropanoid acids. Here, based on the original structure of feruloyl–coenzyme A (CoA) synthetase (FCS) from Streptomyces sp. V-1, we engineered five substrate-binding domains to match specific phenylpropanoid acids. FcsCIAE407A/K483L, FcsMAE407R/I481R/K483R, FcsHAE407K/I481K/K483I, FcsCAE407R/I481R/K483T, and FcsFAE407R/I481K/K483R showed 9.96-, 10.58-, 4.25-, 6.49-, and 8.71-fold enhanced catalytic efficiency for degrading CoA thioesters of cinnamic acid, 4-methoxycinnamic acid, 4-hydroxycinnamic acid, caffeic acid, and ferulic acid, respectively. Molecular dynamics simulation illustrated that novel substrate-binding domains formed strong interaction forces with substrates’ methoxy/hydroxyl group and provided hydrophobic/alkaline catalytic surfaces. Five recombinant E. coli with FCS mutants were constructed with the maximum benzaldehyde, p-anisaldehyde, p-hydroxybenzaldehyde, protocatechualdehyde, and vanillin productivity of 6.2 ± 0.3, 5.1 ± 0.23, 4.1 ± 0.25, 7.1 ± 0.3, and 8.7 ± 0.2 mM/h, respectively. Hence, our study provided novel and efficient enzymes for the bioconversion of phenylpropanoid acids into aromatic aldehydes.