Cross-talk between energy supply and drug translocation in the ABC transporter Pdr5

ABC 转运蛋白 Pdr5 中能量供应和药物易位之间的串扰

• 批准号: 492624709
• 负责人: Professor Dr. Lutz Schmitt
• 金额: --
• 依托单位: Lehrstuhl für Biochemie I
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/492624709?language=en
• 关键词: Cross; talk; between; energy; supply

Multidrug resistance (MDR) is a major concern in public health and in particular with the relentless rise of microbes that become resistant to multiple therapies. Among the arsenal used by microorganisms to resist to therapeutic drugs, a major threat is the use of multidrug transporters that expel many structurally unrelated drugs. Some of these polyspecific transporters use ATP as the energy source and they belong to a very large superfamily, the ATP-Binding Cassette (ABC) proteins. All members of this ABC family, primarily membrane proteins, possess conserved sequence motifs involved in ATP binding and hydrolysis and it was originally suggested that they work according to a conserved ‘unified’ mechanism of energy transduction. However, due to the versatility of function and many different topologies of ABC transporters, how and which energy is used may vary considerably, and subclasses of transporters with singular features are likely to emerge. For instance, even if all ABC transporters possess two ATP-binding sites, they are either symmetric, both sites being able to hydrolyse ATP, or asymmetric with one degenerate site, unable, or poorly able, to hydrolyse ATP. For example, Pdr5 is a full-length yeast MDR ABC transporter and the most extreme example of an ABC transporter containing a degenerated ATP binding site as all conserved motifs involved in ATP binding show exchange of the catalytical relevant amino acids. With respect to energy supply, Pdr5 seems to adapt its nucleotide dependency according to the drug transported. Moreover, recent results obtained with Pdr5 strongly support that this transporter co-transport drugs and protons and this might be relevant for other multidrug ABC transporters as well. These singularities among MDR ABC transporters warrant a detailed investigation of their molecular mechanisms with a particular focus on their energy requirement. We will therefore address central questions regarding (i) the mechanism of co-transport of protons during the transport cycle of Pdr5, (ii) specificity for certain nucleotides also in dependence of the transport substrate, (iii) continue our structural analysis of substrates and inhibitors to understand what make a substrate a substrate and an inhibitor to an inhibitor and (vi) determine the underlying dynamics and energetics during the transport cycle of Pdr5. The complementary expertise of the two teams and their knowledge of this yeast transporter as well as in electrophysiology and single molecule fluorescence techniques will be an asset to tackle these burning questions and unravel the catalytic mechanisms of Pdr5.

多药耐药性（MDR）是公共卫生中的一个主要问题，特别是随着对多种疗法产生耐药性的微生物的不断增加。在微生物用来抵抗治疗药物的武器库中，一个主要的威胁是使用多药物转运蛋白，它可以排出许多结构上不相关的药物。这些多特异性转运蛋白中的一些使用ATP作为能量来源，并且它们属于一个非常大的超家族，ATP结合盒（ABC）蛋白。这个ABC家族的所有成员，主要是膜蛋白，都具有参与ATP结合和水解的保守序列基序，最初认为它们根据保守的“统一”能量转导机制工作。然而，由于ABC运输机的功能和许多不同的拓扑结构的多功能性，如何以及使用哪种能量可能会有很大的不同，并且可能会出现具有单一功能的运输机子类。例如，即使所有ABC转运蛋白都具有两个ATP结合位点，它们也是对称的，两个位点都能够水解ATP，或者是不对称的，具有一个简并位点，不能或很难水解ATP。例如，Pdr5是全长酵母MDR ABC转运蛋白，并且是含有简并ATP结合位点的ABC转运蛋白的最极端的实例，因为参与ATP结合的所有保守基序都显示催化相关氨基酸的交换。在能量供应方面，Pdr5似乎根据药物转运来适应其核苷酸依赖性。此外，最近获得的结果与Pdr5强烈支持，这种转运共转运药物和质子，这可能是相关的其他多药ABC转运以及。 MDR ABC转运蛋白之间的这些奇异性保证了对它们的分子机制的详细研究，特别关注它们的能量需求。因此，我们将解决关于（i）在Pdr5的转运循环期间质子共转运的机制，（ii）也依赖于转运底物的某些核苷酸的特异性，（iii）继续我们对底物和抑制剂的结构分析，以了解是什么使底物成为抑制剂的底物和抑制剂，以及（vi）确定Pdr5运输周期中的潜在动力学和能量学。这两个团队的互补专业知识以及他们对这种酵母转运蛋白以及电生理学和单分子荧光技术的了解将成为解决这些紧迫问题和解开Pdr5催化机制的资产。