Structure and function of fungal adhesins

gpi连接的细胞壁蛋白家族，被称为真菌粘附素，赋予出芽酵母酿酒酵母，人类致病酵母念珠菌和工业相关酵母毕赤酵母独特的表面粘附特性。到目前为止，大多数这些蛋白质赋予表面辨别和粘附的详细特征在很大程度上是未知的。在上一次资助期间，我们在原子分辨率下确定了葡萄球菌絮凝素Flo5和Flo11以及葡萄球菌粘附素Epa1的粘附域的晶体结构。在下一个资助期，我们将进一步研究酿酒葡萄球菌、光面葡萄球菌和帕斯德酵母中碳水化合物结合黏附素的结构和功能特性。具体来说，我们将分析从C. glabrata Epa和Pwp家族中选择的成员的n端配体结合域，以及来自P. pastoris的flo5相关的推定粘附素。通过糖聚糖微阵列分析筛选相应的重组粘附素结构域，并通过x射线晶体学分析确定其结晶和结构。以酿酒酵母为异源系统，通过功能分析进一步研究不同黏附素配体结合域的体内特性。我们还将以葡萄球菌絮凝蛋白Flo5为模型，确定其结构和功能尚不清楚的真菌粘附素的中心重复B结构域的生化特性。

A family of GPI-linked cell wall proteins, known as fungal adhesins, confers unique surface adhesion properties in the budding yeast Saccharomyces cerevisiae, the human pathogenic yeast Candida glabrata and the industrially relevant yeast Pichia pastoris. The detailed features of most of these proteins conferring surface discrimination and adherence were so far largely unknown. During the last funding period, we determined crystal structures of the adhesion domains of the S. cerevisiae floccu-lins Flo5 and Flo11 as well as of the C. glabrata adhesin Epa1 at atomic resolutions. For the next funding period, we propose to elucidate the structural and functional properties of further carbohy-drate-binding adhesins from S. cerevisiae, C. glabrata and P. pastoris in vitro and in vivo. Specifically, we will analyze N-terminal ligand-binding domains of selected members from the C. glabrata Epa and Pwp families and of Flo5-related putative adhesins from P. pastoris. Respective recombinant adhesin domains will be screened for specific ligand binding by glycan microarray analysis and subjected to crystallization and structure determination by X-ray crystallographic analysis. The in vivo properties of the different adhesin ligand-binding domains will further be investigated by functional analysis using S. cerevisiae as a heterologous system. We will also determine the biochemical properties of the central, repetitive B domains of fungal adhesins, whose structures and functions are not known in detail yet, by using the S. cerevisiae flocculin Flo5 as a model.