基于PDR转运蛋白增强重组酿酒酵母分泌β-胡萝卜素能力的分子机制

产物积累对细胞产生毒性和产物存储空间不足是制约β-胡萝卜素过量合成的瓶颈。研究发现，酿酒酵母中的多效耐药性蛋白Pdr5和Pdr10能够结合并转运β-胡萝卜素至胞外。本研究基于反向代谢工程的原理，以多株合成不同水平的β-胡萝卜素重组酿酒酵母菌株为研究对象，利用启动子工程技术，对PDR5和PDR10基因以及能量模块VHb和PtxD基因的表达水平进行精确和协同调控，合理增加PDR蛋白和ATP合成水平，以增强细胞分泌β-胡萝卜素的能力，并改善细胞生长，进一步提高重组酿酒酵母合成β-胡萝卜素的水平。本研究对于揭示微生物细胞应答类胡萝卜素过量积累的生理调控机制，解决制约类胡萝卜素合成的瓶颈问题将具有重要的学术意义和应用价值。同时，研究结果可为其它类异戊二烯产物的研究提供有益的借鉴。

The toxicity of product accumulation on cells and the insufficient storage space are the bottlenecks restricting the excessive synthesis of β-carotene. The multiple drug resistant proteins Pdr5 and Pdr10 of Saccharomyces cerevisiae can bind and transport β-carotene to the extracellular environment. In this study, based on the principle of reverse metabolic engineering, the recombinant Saccharomyces cerevisiae strains producing different levels of β-carotene were used as research object, the expressions of PDR5, PDR10, and energy module VHb and PtxD were accurately and synergistically regulated through promoter engineering to increase the secretion of β-carotene and improve the cell growth, and further improve the production of β-carotene. These results are expected to reveal the physiological regulation of cells in response to excessive accumulation of products and solve the bottleneck problem of restricting efficient biosynthesis of carotenoid. This study can also provide some valuable references for research of other isoprenoids production by microorganism.