吡咯喹啉醌(PQQ)合成基因对PQQ产量的影响

The Effect on Production of PQQ Directed by the Pyrroloquinline Quinone Biosynthesis Genes' Copy Number

将携带新辅基吡咯喹啉醌合成基因的克隆载体pRK310 经三亲本杂交,分别导入M.extorquens.AM1 及其突变体3b 和D2 中,可不同程度增加pqq 基因的拷贝数. 在基因复制水平构建了8 个工程菌,使PQQ产量提高了0.84～5.6 倍. 结果表明,结构上成簇的pqq 基因在功能上是密切相关、协调作用的,单个或部分pqq基因对PQQ合成的贡献是有限的,pqq 基因之间的比例和相互作用对PQQ 的合成量是有重要意义的.pqq 基因簇中起转录衰减作用的反向重复序列可能是pqq 基因正常转录所必需的.

Genes of pyrroloquinline quinone biosynthesis,cloned in a clone vector pRK310,were introduced into M.extorquens.AM1 and mutant 3b、D2 by tri\|parental\|mating. So that the copies of some pqq genes were improved and the production of PQQ were 0.84~5.6 times higher than before. This is the construction of gene\|enginering\|bacterial at the level of DNA replication. The results suggested that clusted pqq genes were cooperated in function, one or some of them had little effect on the production of PQQ. The proportion and cooperation of pqq genes are of great importance in PQQ's production. Moreover, the pqq cluster was introduced into M.extorquens.AM1 and mutant D2 after being cut out of the inverted\|repeat\|sequence which is possible responsible for the reducing of pqq genes'transcription and located in downstream of pqqA gene and 5' terminal of pqqB gene. The effect suggested that the repeat\|sequence was essential for pqq genes'transcription.