Chan B, Busby S
School of Biochemistry, University of Birmingham, U.K.
Gene. 1989 Dec 14;84(2):227-36. doi: 10.1016/0378-1119(89)90496-4.
Specific nucleotide (nt) sequences in the -35 region are not essential for galP1 promoter activity, whereas nt sequences in the spacer region are needed for transcription initiation: a G:C base pair at nt -14 and sequences upstream from this position are necessary. In the absence of these sequences, transcription initiation is dependent on the insertion of oligodeoxyribonucleotides carrying -35 region consensus hexamer sequences. Additionally, for maximal promoter activity, specific sequences just upstream from nt -49 are required. Because galP1 carries no sequence resembling the -35 region consensus hexamer, we propose that recognition by RNA polymerase proceeds via an unusual mechanism involving contacts upstream from the -10 hexamer, distortion of the spacer region and a contact upstream from nt -49.
-35区域中的特定核苷酸（nt）序列对于galP1启动子活性并非必需，而间隔区中的nt序列是转录起始所必需的：nt -14处的G:C碱基对以及该位置上游的序列是必需的。在没有这些序列的情况下，转录起始依赖于携带-35区域共有六聚体序列的寡脱氧核糖核苷酸的插入。此外，为了实现最大启动子活性，需要nt -49上游的特定序列。由于galP1没有与-35区域共有六聚体相似的序列，我们提出RNA聚合酶的识别通过一种不同寻常的机制进行，该机制涉及与-10六聚体上游的接触、间隔区的扭曲以及nt -49上游的接触。
