Department of Biology, Indiana University , Bloomington, Indiana 47405, United States.
J Phys Chem B. 2013 Sep 12;117(36):10492-503. doi: 10.1021/jp405802e. Epub 2013 Sep 4.
To colonize surfaces, the bacterium Caulobacter crescentus employs a polar polysaccharide, the holdfast, located at the end of a thin, long stalk protruding from the cell body. Unlike many other bacteria which adhere through an extended extracellular polymeric network, the holdfast footprint area is tens of thousands times smaller than that of the total bacterium cross-sectional surface, making for some very demanding adhesion requirements. At present, the mechanism of holdfast adhesion remains poorly understood. We explore it here along three lines of investigation: (a) the impact of environmental conditions on holdfast binding affinity, (b) adhesion kinetics by dynamic force spectroscopy, and (c) kinetic modeling of the attachment process to interpret the observed time-dependence of the adhesion force at short and long time scales. A picture emerged in which discrete molecular units called adhesins are responsible for initial holdfast adhesion, by acting in a cooperative manner.
为了在表面定殖，弯杆菌（Caulobacter crescentus）利用位于从细胞主体伸出的细长柄末端的极性多糖，即固着器。与许多通过延伸的细胞外聚合网络附着的其他细菌不同，固着器的附着面积比细菌总横截面积小数万倍，因此对附着提出了非常高的要求。目前，固着器附着的机制仍知之甚少。我们沿着三条研究路线来探讨这个问题：（a）环境条件对固着结合亲和力的影响，（b）通过动态力谱学研究粘附动力学，以及（c）对附着过程的动力学建模，以解释在短时间和长时间尺度上观察到的粘附力的时间依赖性。结果显示，称为黏附素的离散分子单元以协同作用的方式负责初始固着附着。
