Smith C P, Chater K F
John Innes Institute, Norwich, U.K.
J Mol Biol. 1988 Dec 5;204(3):569-80. doi: 10.1016/0022-2836(88)90356-7.
The pathway for glycerol catabolism in Streptomyces coelicolor is determined by the gylABX operon. The sequence of about 1500 base-pairs (bp) preceding the structural genes of the operon has been determined, and related to a detailed transcriptional analysis of this region. The gylABX operon contains two major promoters, gylP1 and gylP2, separated by 50 bp. Both promoters are glycerol-inducible and glucose-repressible. A 900-base transcription unit, gylR, is situated immediately upstream of the gylABX promoter region and contains an open reading frame for a 27,600 Mr protein. The predicted sequence of this protein contains a region that is similar to the helix-turn-helix domains of certain DNA-binding proteins. Transcription of gylR is also glycerol-inducible, but is only weakly glucose-repressible, and initiates predominantly from a single promoter, gylRp. The three promoters, gylRP, gylP1 and gylP2, each resemble the "typical" prokaryotic consensus promoter sequence. The DNA sequence of the gylR and gylABX promoter regions share some striking features. These include almost identical operator-like elements (segments of which are tandemly repeated around gylRP) and tracts of alternating purine-pyrimidine residues.
天蓝色链霉菌中甘油分解代谢途径由gylABX操纵子决定。已确定该操纵子结构基因之前约1500个碱基对（bp）的序列，并将其与该区域的详细转录分析相关联。gylABX操纵子包含两个主要启动子，gylP1和gylP2，相隔50 bp。两个启动子均受甘油诱导且受葡萄糖抑制。一个900碱基的转录单位gylR，位于gylABX启动子区域的紧邻上游，包含一个编码27,600 Mr蛋白质的开放阅读框。该蛋白质的预测序列包含一个与某些DNA结合蛋白的螺旋-转角-螺旋结构域相似的区域。gylR的转录也是甘油诱导型的，但仅受弱葡萄糖抑制，且主要从单个启动子gylRp起始。三个启动子，gylRP、gylP1和gylP2，均类似于“典型”的原核共有启动子序列。gylR和gylABX启动子区域的DNA序列具有一些显著特征。这些特征包括几乎相同的类操纵元件（其片段在gylRP周围串联重复）以及嘌呤-嘧啶残基交替的区域。
