Mechanistic analysis of catalysis and regulation of the fungal proton pump Pma1

在所有生物体中，一层脂质膜将每个细胞的“内部”与“外部”分开。为了与周围环境交换物质和信息，每个细胞的外膜上都嵌入了各种运输蛋白。这些蛋白质控制着什么可以进入和离开细胞，它们是“内部”和“外部”世界之间非常重要的看门人。这种膜运输蛋白的一个大家族实际上是“泵”离子穿过膜，从而建立重要的不平衡，然后促进其他过程，如营养摄取，神经兴奋或肌肉收缩。其中一种被称为Pma1的泵在所有真菌的膜中产生一种至关重要的质子梯度。作为一种分子机器，它可以将最小的离子——单个质子——抽到膜上，这不仅本身很有趣，而且从经济学的角度来看也很重要：Pma1在人类和动物中都不存在，植物也有一个相关但不同的质子泵。由于真菌不能在没有Pma1的情况下存活，它可能成为新型杀菌剂的目标，对动物、人类或植物的有害影响风险较低。鉴于有害真菌对目前广泛用于保护植物和作物免受真菌害虫侵害的杀菌剂出现耐药性，迫切需要这样的新靶点。该研究项目将通过结合最先进的生物化学和生物物理方法，揭示Pma1如何通过膜运输质子，使分子本身可见于人眼。该项目将使人们更深入地了解实际的质子泵送过程，并将为开发新的杀菌剂提供必要的信息。

A lipid membrane separates the 'inside' from the 'outside' of each cell in all living organisms. In order to exchange material and information with its surroundings, every cell possesses various transport proteins embedded in its outer membrane. These proteins control what can enter and exit cells, and they are very important gate-keepers between the 'inside' and 'outside' worlds.One large family of such membrane transport proteins literally 'pump' ions across the membrane, thereby building up important imbalances, which are then fuelling other processes, such as nutrient uptake, nerve excitation, or muscle contraction. One such pump, called Pma1, generates a fundamentally important proton gradient in the membranes of all fungi. As a molecular machine that specifically pumps the smallest of all ions - single protons - across the membrane, it is not only interesting in itself, but it is also important from an economic point of view: Pma1 does not exist in humans or animals, and plants have a related but different proton pump. Since fungi cannot survive without Pma1, it could be the target of novel fungicides with a low risk of harmful effects on animals, humans or plants. Such new targets are urgently needed in light of emerging resistances of harmful fungi against those fungicides which are currently in extensive use to protect plants and crops from fungal pests.This research project will reveal how Pma1 transports protons across membranes, by combining state-of-the-art biochemical and biophysical methods to make the molecule itself visible to the human eye. The project will lead to a deeper understanding of the actual proton pumping process, and it will provide the information necessary to develop new fungicides.