Aquaporins as facilitator for CO2 diffusion

细胞内二氧化碳的扩散对大多数生物体的生存具有重要意义。无论二氧化碳是作为动物等催化反应的副产品处理，还是光合作用过程所需要的碳同化，它都必须通过细胞膜。最近的研究表明，除了膜双层扩散外，水通道蛋白可能促进了二氧化碳的运输。尽管它很重要，但这种水通道蛋白相关的二氧化碳运输机制尚不清楚。我们以前的研究表明，水通道蛋白四聚体构建的结构是两个基本功能成分之一。另一种结构表现在蛋白质的氨基末端。本提案的目的是通过酵母表达系统中蛋白质位点的选择性修饰和随后的功能分析来鉴定和表征这些蛋白质区域。本课题的研究结果将进一步揭示水通道蛋白介导二氧化碳扩散的分子机制。它们将有助于我们理解这个与生命相关的扩散过程。

Cellular CO2 diffusion is significant for the survival of the majority of living organisms. No matter if CO2 has to be disposed as a spin-off product from catalytic reactions of e.g. animals or is required for carbon assimilation of photosynthetic processes, it has to pass cellular membranes. Recent findings indicate that besides membrane bilayer diffusion, an aquaporin facilitated CO2 transport is likely. Despite its importance, the mechanism of this aquaporin related CO2 transport is unclear. Our previous studies suggested for a structure build by an aquaporin tetramer as one of two essential functional components. The other structure is represented in the protein’s amino terminus. The objective of this proposal is to identify and characterize these protein regions by selective modifications of protein sites and subsequent functional analysis in a yeast expression system. The results of this project will establish a picture about the molecular mechanism of aquaporin mediated CO2 diffusion. They will contribute to our understanding of this diffusion process, which is relevant for life.