BIOTINYL 5'-ADENYLATE - COREPRESSOR ROLE IN THE REGULATION OF THE BIOTIN GENES OF ESCHERICHIA-COLI K-12
BIOTINYL 5'-ADENYLATE - COREPRESSOR ROLE IN THE REGULATION OF THE BIOTIN GENES OF ESCHERICHIA-COLI K-12
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DOI：
10.1073/pnas.76.11.5592
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
EISENBERG, MA
中科院分区：
文献类型：
--
作者：
PRAKASH, O;EISENBERG, MA
DNA过滤结合技术被用来研究生物素阻遏物和操纵位点的相互作用。根据生物素饱和曲线，计算半最大结合浓度（K0.5）为1 μ M。在一项类似的研究中，在体外转录-翻译偶联系统中，生物素作为辅阻遏物，阻遏的K0.5为7.1 nM。这种超过2个数量级的显著差异归因于体外系统中部分纯化的阻遏物制剂对生物素的活化。生物素、ATP和阻遏物形成的活化产物经纸层析和异羟肟酸形成鉴定为生物素基5“-腺苷酸。合成的生物素基5“-腺苷酸在体外系统中与生物素一样有效（K0.5，10 nM），并且在DNA结合测定中比生物素有效得多（K0.5 1.1 nM对1 μ M）。这些研究表明，生物素基5“-腺苷酸在生物素基因的调节中比生物素本身具有更直接的作用。
A DNA filter-binding technique was used to study the interaction of the biotin repressor and operator site. From a biotin saturation curve, the concentration for half-maximal binding (K0.5) was calculated to be 1 .mu.M. In a similar study with the in vitro coupled transcription-translation system in which biotin served as the corepressor, the K0.5 for repression was 7.1 nM. This marked difference of over 2 orders of magnitude was attributed to the activation of biotin by the partially purified repressor preparation in the in vitro system. The activated product formed from biotin, ATP and repressor preparation was identified as biotinyl 5''-adenylate by paper chromatography and hydroxamic acid formation. Synthetic biotinyl 5''-adenylate was as effective as biotin in the in vitro system (K0.5, 10 nM) and much more effective than biotin in the DNA-binding assay (K0.5 1.1 nM vs. 1 .mu.M). These studies indicate that biotinyl 5''-adenylate has a more direct role in the regulation of the biotin genes than does biotin per se.