Hoshino T, Fujii R, Nakahara T
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
Appl Environ Microbiol. 1993 Sep;59(9):3150-3. doi: 10.1128/aem.59.9.3150-3153.1993.
We have cloned and sequenced a 1.5-kb chromosomal fragment of Thermus thermophilus which promoted the overproduction of carotenoids in T. thermophilus. An open reading frame (ORF-A) coding for a polypeptide with 289 amino acids was responsible for carotenoid overproduction. The putative ORF-A protein showed significant homology with the amino acid sequences of crtB gene products (phytoene syntheses) of other microorganisms. The clone containing the ORF-A on a multicopy plasmid produced about three times as much carotenoid as that produced by the host strain, suggesting that the crtB gene product is a rate-limiting enzyme for carotenoid biosynthesis in T. thermophilus.
我们克隆并测序了嗜热栖热菌的一段1.5kb染色体片段，该片段可促进嗜热栖热菌中类胡萝卜素的过量产生。一个编码含289个氨基酸的多肽的开放阅读框（ORF-A）负责类胡萝卜素的过量产生。推测的ORF-A蛋白与其他微生物的crtB基因产物（八氢番茄红素合成酶）的氨基酸序列具有显著同源性。在多拷贝质粒上含有ORF-A的克隆产生的类胡萝卜素约为宿主菌株产生量的三倍，这表明crtB基因产物是嗜热栖热菌类胡萝卜素生物合成的限速酶。
