Structural Study of Transmembrane Domain of Band 3 Protein

在本项目中，我们对带3蛋白的结构和功能进行了研究，并通过对带3蛋白的研究，提出了多跨多孔膜蛋白的新概念。这类蛋白质的跨膜结构域可分为三类，即跨膜多肽的亲水环状连接(第1类)、通过肽-肽相互作用嵌入的部分(第2类)和由肽-脂相互作用嵌入的部分(第3类)。多孔膜蛋白的第二类多肽被发现稳定地存在于脂质双层中，而没有被认为是跨膜片段所必需的多肽-脂类相互作用。3类多肽相当于双位膜蛋白的单跨段。三种不同的实验，即蛋白水解法、带3蛋白的化学修饰和细胞自由转录/翻译实验系统被用来对跨膜多肽进行分类

In this project, we have investigated the band 3 protein structure and function and introduced a novel concept in multi-spanning polytopic membrane proteins revealed by the study on band 3 protein. The transmembrane domain of such proteins can be divided into three categories, that is, hydrophilic loops connecting of transmembrane peptides (category 1), portions being embedded by the peptide-peptide interactions (category 2) and portions being embedded by the peptide-lipid interactions (category 3). Category 2 peptides of polytopic membrane proteins were found to stably reside in the lipid bilayer without peptide-lipid interactions which had been thought to be essential for transmembrane segments. Category 3 peptide is equivalent to the single-spanning segment of a bitopic membrane protein. Three different experiments, that is, a proteolytic digestion method, a chemical modification on band 3 protein and a cell free transcription/translation experiment system, were used to categorize the transmembrane peptides