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

在所有生物体中，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，每个细胞都具有嵌入其外膜的各种转运蛋白。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守门人。一个大家族的这种膜转运蛋白字面上“泵”离子穿过膜，从而建立重要的不平衡，然后助长其他过程，如营养吸收，神经兴奋，或肌肉收缩。其中一个泵，称为Pma 1，在所有真菌的膜中产生一个非常重要的质子梯度。作为一种分子机器，它专门泵送所有离子中最小的离子-单个质子-穿过膜，它不仅本身很有趣，而且从经济角度来看也很重要：Pma 1不存在于人类或动物中，植物有一个相关但不同的质子泵。由于真菌在没有Pma 1的情况下无法生存，因此它可能成为新型杀真菌剂的目标，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农作物免受真菌害虫侵害的杀菌剂产生了抗药性，迫切需要此类新靶标。该研究项目将揭示Pma 1如何通过结合最先进的生物化学和生物物理方法使分子本身对人眼可见来跨膜运输质子。该项目将导致对实际质子泵送过程的更深入了解，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.