Merson-Davies L A, Cundliffe E
Department of Biochemistry, University of Leicester, UK.
Mol Microbiol. 1994 Jul;13(2):349-55. doi: 10.1111/j.1365-2958.1994.tb00428.x.
The tyllBA region of the tylosin biosynthetic gene cluster of Streptomyces fradiae contains at least five open reading frames (ORFs). ORF1 (tylI) encodes a cytochrome P450 and mutations in this gene affect macrolide ring hydroxylation. The product of ORF2 (tylB) belongs to a widespread family of proteins whose functions are speculative, although tylB mutants are defective in the biosynthesis or addition of mycaminose during tylosin production. ORFs 3 and 4 (tylA1 and tylA2) encode delta TDP-glucose synthase and delta TDP-glucose dehydratase, respectively, enzymes responsible for the first two steps common to the biosynthesis of all three deoxyhexose sugars of tylosin via the common intermediate, delta TDP-4-keto, 6-deoxyglucose. ORF5 encodes a thioesterase similar to one encoded in the erythromycin gene cluster of Saccharopolyspora erythraea.
弗氏链霉菌泰乐菌素生物合成基因簇的tyllBA区域至少包含五个开放阅读框（ORF）。ORF1（tylI）编码一种细胞色素P450，该基因中的突变会影响大环内酯环的羟基化。ORF2（tylB）的产物属于一类广泛存在的蛋白质家族，其功能尚不清楚，尽管tylB突变体在泰乐菌素生产过程中，在霉胺糖的生物合成或添加方面存在缺陷。ORF3和ORF4（tylA1和tylA2）分别编码δ-TDP-葡萄糖合酶和δ-TDP-葡萄糖脱水酶，这两种酶负责通过共同中间体δ-TDP-4-酮、6-脱氧葡萄糖，合成泰乐菌素所有三种脱氧己糖糖的生物合成的前两个步骤。ORF5编码一种硫酯酶，类似于糖多孢红霉菌红霉素基因簇中编码的一种硫酯酶。
