Ponnuraj Karthe, Bowden M Gabriela, Davis Stacey, Gurusiddappa S, Moore Dwight, Choe Damon, Xu Yi, Hook Magnus, Narayana Sthanam V L
School of Optometry and Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Cell. 2003 Oct 17;115(2):217-28. doi: 10.1016/s0092-8674(03)00809-2.
Gram-positive pathogens such as staphylococci contain multiple cell wall-anchored proteins that serve as an interface between the microbe and its environment. Some of these proteins act as adhesins and mediate bacterial attachment to host tissues. SdrG is a cell wall-anchored adhesin from Staphylococcus epidermidis that binds to the Bbeta chain of human fibrinogen (Fg) and is necessary and sufficient for bacterial attachment to Fg-coated biomaterials. Here, we present the crystal structures of the ligand binding region of SdrG as an apoprotein and in complex with a synthetic peptide analogous to its binding site in Fg. Analysis of the crystal structures, along with mutational studies of both the protein and of the peptide, reveals that SdrG binds to its ligand with a dynamic "dock, lock, and latch" mechanism. We propose that this mechanism represents a general mode of ligand binding for structurally related cell wall-anchored proteins of gram-positive bacteria.
革兰氏阳性病原体，如葡萄球菌，含有多种细胞壁锚定蛋白，这些蛋白充当微生物与其环境之间的界面。其中一些蛋白作为粘附素，介导细菌与宿主组织的附着。SdrG是一种来自表皮葡萄球菌的细胞壁锚定粘附素，它与人纤维蛋白原（Fg）的Bβ链结合，对于细菌附着于Fg包被的生物材料是必需且充分的。在此，我们展示了SdrG配体结合区域作为脱辅基蛋白以及与一种类似于其在Fg中结合位点的合成肽形成复合物时的晶体结构。对晶体结构的分析，以及对该蛋白和肽的突变研究表明，SdrG通过一种动态的“对接、锁定和闩锁”机制与其配体结合。我们提出，这种机制代表了革兰氏阳性细菌结构相关的细胞壁锚定蛋白配体结合的一种普遍模式。
