Sequence and structure-based method to predict diacylglycerol lipases in protein sequence.

Lipase enzymes play a central role in biotechnology and the food industry. Diacylglyceride lipases (DAG) have received considerable attention due to their physiological significance and potential industrial usage. However, compared to the wide application of triacylglycerol (TAG) lipases, DAG lipases have a limited application due to their low thermostability and specific activity. The molecular basis of substrate specificity of DAG lipases remains elusive, making structure-guided engineering of TAG to DAG lipase difficult. Besides, the number of available DAG lipases is limited compared to TAG lipases. In the current study, we identified structural consensus motifs of DAG lipases that contribute to their DAG specificity on a structural comparison of DAG and TAG lipases. To find potential DAG lipases, sequence motifs and predicted secondary structures were used to screen millions of protein sequences and predict new DAG lipases. In total, 83 new putative DAG lipases were identified. The predicted DAG lipases were validated by expression of randomly chosen putative DAG lipases followed by functional assay for their DAG and TAG specific activity. The reported method is efficient and cost-effective for discovering new DAG lipases used in the food industry after the required characterization to meet potential application needs.