Single-Cell and Single-Molecule Analysis Unravels the Multifunctionality of the Staphylococcus aureus Collagen-Binding Protein Cna.
Single-Cell and Single-Molecule Analysis Unravels the Multifunctionality of the Staphylococcus aureus Collagen-Binding Protein Cna.
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DOI：
10.1021/acsnano.6b08404
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发表时间：
2017-02
期刊：
影响因子：
17.1
通讯作者：
Claire Valotteau;Valeria Prystopiuk;G. Pietrocola;S. Rindi;D. Peterle;V. De Filippis;T. Foster;P. Speziale;Y. Dufrêne
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文献类型：
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作者：
Claire Valotteau;Valeria Prystopiuk;G. Pietrocola;S. Rindi;D. Peterle;V. De Filippis;T. Foster;P. Speziale;Y. Dufrêne
胶原蛋白结合蛋白 Cna 是金黄色葡萄球菌的原型细胞表面蛋白，在发病过程中发挥重要的生理功能。虽然已确定 Cna 通过高亲和力胶原拥抱机制与胶原 (Cn) 结合，但该蛋白是否参与其他配体结合机制尚不清楚。在这里，我们使用原子力显微镜证明 Cna 通过与胶原拥抱不同的结合机制介导与两种结构和功能不同的宿主蛋白（即补体系统蛋白 C1q 和细胞外基质蛋白层粘连蛋白 (Lam)）的附着。我们表明，单个 Cna-C1q 和 Cna-Lam 键比高亲和力 Cna-Cn 键弱得多，并且它们的形成不需要 Cna 的 B 区。在全细胞水平上，我们发现细菌对 C1q 底物的粘附仅涉及一个（或两个）分子键，而对 Lam 的粘附是由多个键介导的，因此表明多价或协同相互作用可能会增强粘附强度。 C1q 和 Lam 相互作用都可以被针对 Cna 最小 Cn 结合域的单克隆抗体有效阻断。这些结果表明，Cna 是一种多功能蛋白，能够通过不同于经典胶原蛋白拥抱的机制与多个宿主配体结合。
The collagen-binding protein Cna is a prototype cell surface protein from Staphylococcus aureus which fulfils important physiological functions during pathogenesis. While it is established that Cna binds to collagen (Cn) via the high-affinity collagen hug mechanism, whether this protein is engaged in other ligand-binding mechanisms is poorly understood. Here, we use atomic force microscopy to demonstrate that Cna mediates attachment to two structurally and functionally different host proteins, i.e., the complement system protein C1q and the extracellular matrix protein laminin (Lam), through binding mechanisms that differ from the collagen hug. We show that single Cna-C1q and Cna-Lam bonds are much weaker than the high-affinity Cna-Cn bond and that their formation does not require the B-region of Cna. At the whole cell level, we find that bacterial adhesion to C1q-substrates involves only one (or two) molecular bond(s), while adhesion to Lam is mediated by multiple bonds, thus suggesting that multivalent or cooperative interactions may enhance the strength of adhesion. Both C1q and Lam interactions can be efficiently blocked by monoclonal antibodies directed against the minimal Cn-binding domain of Cna. These results show that Cna is a multifunctional protein capable of binding to multiple host ligands through mechanisms that differ from the classical collagen hug.