PUTA PROTEIN, A MEMBRANE-ASSOCIATED FLAVIN DEHYDROGENASE, ACTS AS A REDOX-DEPENDENT TRANSCRIPTIONAL REGULATOR
PUTA PROTEIN, A MEMBRANE-ASSOCIATED FLAVIN DEHYDROGENASE, ACTS AS A REDOX-DEPENDENT TRANSCRIPTIONAL REGULATOR
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DOI：
10.1073/pnas.90.9.4295
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发表时间：
1993-05-01
影响因子：
11.1
通讯作者：
MALOY, S
中科院分区：
文献类型：
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作者：
DESPICER, PO;MALOY, S
在缺乏脯氨酸的情况下，鼠伤寒沙门氏菌的脯氨酸利用（put）操纵子在转录上受到 PutA 蛋白的抑制。 PutA 蛋白还执行脯氨酸分解代谢中的酶促步骤。这两种角色需要 PutA 不同的细胞定位。脯氨酸的分解代谢需要 PutA 与膜结合，因为 PutA 中 FAD 辅因子的再氧化需要电子受体的存在。 put 操纵子的抑制需要 PutA 与细胞质中的 put 控制区 DNA 结合。脯氨酸（诱导剂）的存在对于 PutA 区分其作为酶或阻遏物的作用是必要的，但还不够。阻止 PutA 蛋白与 put 控制区结合的两个条件是 (i) 当脯氨酸和电子受体或细胞质膜存在时或 (ii) 当 PutA 被连二亚硫酸盐还原时。这两种条件增加了 PutA 蛋白的相对疏水性，有利于膜缔合，从而有利于酶活性。
The proline utilization (put) operon of Salmonella typhimurium is transcriptionally repressed by PutA protein in the absence of proline. PutA protein also carries out the enzymatic steps in proline catabolism. These two roles require different cellular localizations of PutA. Catabolism of proline requires PutA to associate with the membrane because reoxidation of the FAD cofactor in PutA needs the presence of an electron acceptor. Repression of the put operon requires PutA to bind to the put control-region DNA in the cytoplasm. The presence of proline, the inducer, is necessary but not sufficient for PutA to discriminate between its roles as an enzyme or as a repressor. Two conditions that prevent PutA protein binding to the put control region are (i) when proline and an electron acceptor or the cytoplasmic membrane are present or (ii) when PutA is reduced by dithionite. These two conditions increase the relative hydrophobicity of PutA protein, favoring membrane association and therefore enzymatic activity.