Shinkawa H, Hatada Y, Okada M, Kinashi H, Nimi O
Department of Fermentation Technology, Faculty of Engineering, Hiroshima University.
J Biochem. 1995 Sep;118(3):494-9. doi: 10.1093/oxfordjournals.jbchem.a124935.
The hrdB homologue was isolated from a streptomycin-producing Streptomyces griseus 2247 strain, which is independent of A-factor. The nucleotide sequence of the cloned DNA fragment revealed the presence of an open reading frame (ORF) of 1,542bp, which predicted a primary product of 514 amino acids and Mr 56,100. The N-terminal sequence of the purified HrdB protein of S. griseus was identical to the amino acid sequence deduced from the nucleotide sequence. The deduced amino acid sequence contains an "rpoD box" conserved in the principal sigma factors of eubacteria, and shows high similarity to the hrdB products of S. coelicolor A3(2)(89.9%) and S. aureofaciens (88.1%). The cloned gene encodes a principal sigma factor of S. griseus. The promoter region was identified by using a promoter-probe vector and by means of primer extensions experiments. The transcription start point is located 158-bp upstream of the initiation codon.
hrdB 同源物是从一株不依赖 A 因子的产链霉素灰色链霉菌 2247 菌株中分离得到的。克隆的 DNA 片段的核苷酸序列显示存在一个 1542bp 的开放阅读框（ORF），预测其初级产物为 514 个氨基酸，分子量为 56,100。灰色链霉菌纯化的 HrdB 蛋白的 N 端序列与从核苷酸序列推导的氨基酸序列相同。推导的氨基酸序列包含在真细菌主要 σ 因子中保守的“rpoD 框”，并与天蓝色链霉菌 A3(2)（89.9%）和金色链霉菌的 hrdB 产物具有高度相似性（88.1%）。克隆的基因编码灰色链霉菌的主要 σ 因子。通过使用启动子探针载体并借助引物延伸实验鉴定了启动子区域。转录起始点位于起始密码子上游 158bp 处。
