The acyl-CoA-binding protein 2 exhibited the highest affinity for palmitoyl-CoA and promoted Monascus pigment production

Abstract

Abstract Purpose The present study aimed to explore the binding ability of acyl-CoA binding protein 2 to fatty acid acyl-CoA esters and its effect on Monascus pigment production in M. ruber CICC41233. Methods The Mracbp2 gene from M. ruber CICC41233 was cloned with a total DNA and cDNA as the templates through the polymerase chain reaction. The cDNA of the Mracbp2 gene fragment was ligated to expression vector pGEX-6P-1 to construct pGEX-MrACBP2, which was expressed in Escherichia coli BL21 to obtain the fusion protein GST-MrACBP2 and then measure the binding ability of fatty acid acyl-CoA esters. Additionally, the DNA of the Mracbp2 gene fragment was ligated to expression vector pNeo0380 to construct pNeo0380-MrACBP2, which was homologously over-expressed in M. ruber CICC41233 to evaluate Monascus pigment production and fatty acid. Results The cloned Mracbp2 gene of the DNA and cDNA sequence was 1525 bp and 1329 bp in length, respectively. The microscale thermophoresis binding assay revealed that the purified GST-MrACBP2 had the highest affinity for palmitoyl-CoA (Kd =70.57 nM). Further, the Mracbp2 gene was homologously overexpressed in M. ruber CICC41233, and a positive transformant M. ruber ACBP-E was isolated. In the Monascus pigments fermentation, the expression level of the Mracbp2 gene was increased by 1.74-fold after 2 days and 2.38-fold after 6 days. The palmitic acid content and biomass in M. ruber ACBP2-E were significantly lower than that in M. ruber CICC41233 on 2 days and 6 days. However, compared with M. ruber CICC41233, the yields of total pigment, ethanol-soluble pigment, and water-soluble pigment in M. ruber ACBP2-E increased by 63.61%, 71.61%, and 29.70%, respectively. Conclusions The purified fusion protein GST-MrACBP2 exhibited the highest affinity for palmitoyl-CoA. The Mracbp2 gene was overexpressed in M. ruber CICC41233, which resulted in a decrease in palmitic acid and an increase in Monascus pigments. Overall, the effect of MrACBP2 on the synthesis of fatty acid and Monascus pigment was explored. This paper explored the effect of MrACBP2 on the fatty acid synthesis and the synthesis of Monascus pigment. The results indicated the regulation of fatty acid synthesis could affect Monascus pigment synthesis, providing a novel strategy for improving the yield of Monascus pigment.