Structure and Function of Prokaryotic Transcription Factors

原核转录因子的结构和功能

• 批准号: 0315283
• 负责人: Thomas Poulos
• 金额: $ 36万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0315283&HistoricalAwards=false
• 关键词: Structure; Function; Prokaryotic; Transcription; Factors

The goal of this research is to better understand structure-function relationships in CooA, a carbon monoxide sensing transcription factor. CooA belongs to the classic helix-turn-helix family of bacterial transcription factors. Transcription factors are proteins that bind to select segments of DNA and regulate the transcription of specific genes that encode specific enzymes. This class of transcription factor are homo-dimers with each monomer consisting of an effector domain that binds small regulatory molecules and a DNA-binding domain that recognizes specific DNA sequences. When the regulatory molecule binds to the effector domain, structural changes occur which enables the protein to bind to DNA regulatory sequences. The bound transcription factor next binds RNA polymerase leading to the transcription of specific genes. With CooA, carbon monoxide is the small molecule effector. Carbon monoxide binds to the heme in each effector domain which promotes DNA binding thus leading to the production of enzymes that oxidize CO as an energy source. Previous research lead to the solution of the CooA crystal structure in the DNA "off" state. What now is needed is the crystal structure of CooA in the DNA-bound form which is the focus of this research. If successful, CooA would be the first transcription factor in this family where the structure of both the DNA-bound and -free forms are known. This will provide critical new information on how an effector molecule can cause such large changes in the DNA-binding region of the molecule.

这项研究的目的是更好地了解一氧化碳感应转录因子COOA中的结构功能关系。 COOA属于经典的细菌转录因子家族。转录因子是与选择DNA片段结合并调节编码特定酶的特定基因的转录的蛋白质。这类转录因子是每个单体由效应域组成的均二聚体，该效应域结合了小调节分子和识别特定DNA序列的DNA结合域。当调节分子与效应域结合时，发生结构变化，使蛋白质能够与DNA调节序列结合。接下来的结合转录因子结合RNA聚合酶导致特定基因的转录。使用COOA，一氧化碳是小分子效应子。碳一氧化碳与每个效应子结构域中的血红素结合，从而促进DNA结合，从而导致氧化CO作为能源的酶的产生。先前的研究导致在DNA“ OFF”状态下的COOA晶体结构解决方案。现在需要的是以DNA结合形式以COOA的晶体结构，这是这项研究的重点。如果成功的话，COOA将是该家族中的第一个转录因子，在该家族中，DNA结合形式和无DNA形式的结构都是已知的。这将提供有关效应分子如何在分子的DNA结合区域引起如此大的变化的关键新信息。