Mechanical Strength and Inhibition of the Staphylococcus aureus Collagen-Binding Protein Cna.
Mechanical Strength and Inhibition of the Staphylococcus aureus Collagen-Binding Protein Cna.
复制标题
机械强度和抑制金黄色葡萄球菌胶原蛋白结合蛋白CNA。
DOI：
10.1128/mbio.01529-16
复制
发表时间：
2016-10-25
期刊：
影响因子：
6.4
通讯作者：
Dufrêne YF
中科院分区：
文献类型：
--
作者：
Herman-Bausier P;Valotteau C;Pietrocola G;Rindi S;Alsteens D;Foster TJ;Speziale P;Dufrêne YF
细菌病原体金黄色葡萄球菌表达多种与宿主细胞外基质蛋白结合的细胞表面黏附蛋白。其中，胶原(CN)结合蛋白CNA在细菌-宿主黏附和免疫逃避中发挥重要作用。虽然众所周知，CNA的A区介导了配体结合，但重复的B区是否具有专用功能尚不清楚。在这里，我们报道了直接测量活细菌上CNA-CN键的机械强度，并量化了针对这种相互作用的单抗(MAb)的抗黏附活性。我们证明了CNA-CN在体内的键强度很强(~1.2nN)，与高亲和力的“胶原拥抱”机制一致。B区是强烈的配体结合所必需的，已被发现作为能够承受高力的弹簧发挥作用。这种以前未描述的B区的机械反应具有生物学意义，因为它提供了一种手段，使A区远离细菌表面，并在高力条件下保持细菌的黏附。我们进一步定量了针对CNA A区的单抗直接在活细菌上的抗黏附活性，而不需要标记或纯化。一些单抗在阻止单细胞黏附方面更有效，这表明它们作为竞争性抑制剂与直接参与配体结合的CNA残基结合。这份报告强调了蛋白质力学在激活葡萄球菌黏附蛋白功能中的作用，并强调了抗体预防葡萄球菌黏附和生物被膜形成的潜力。CnA是金黄色葡萄球菌的一种胶原结合蛋白，参与了金黄色葡萄球菌的发病机制。目前，我们对该蛋白重复B区的功能知之甚少。在这里，我们揭开了CNA在活细菌中的机械强度。我们发现单一的CNA-CN键非常强，反映了通过胶原拥抱机制的高亲和力结合。我们发现，B区的行为就像一个纳米弹簧，能够承受高强度。这种意想不到的机械反应，以前没有对任何葡萄球菌粘附素进行描述，支持B区域具有机械功能的模型，在该模型中，机械功能对于强烈的配体结合是必不可少的。最后，我们评估了抗CNA的单抗的抗黏附活性，表明它们可以用于抑制金黄色葡萄球菌的黏附。
The bacterial pathogen Staphylococcus aureus expresses a variety of cell surface adhesion proteins that bind to host extracellular matrix proteins. Among these, the collagen (Cn)-binding protein Cna plays important roles in bacterium-host adherence and in immune evasion. While it is well established that the A region of Cna mediates ligand binding, whether the repetitive B region has a dedicated function is not known. Here, we report the direct measurement of the mechanical strength of Cna-Cn bonds on living bacteria, and we quantify the antiadhesion activity of monoclonal antibodies (MAbs) targeting this interaction. We demonstrate that the strength of Cna-Cn bonds in vivo is very strong (~1.2 nN), consistent with the high-affinity “collagen hug” mechanism. The B region is required for strong ligand binding and has been found to function as a spring capable of sustaining high forces. This previously undescribed mechanical response of the B region is of biological significance as it provides a means to project the A region away from the bacterial surface and to maintain bacterial adhesion under conditions of high forces. We further quantified the antiadhesion activity of MAbs raised against the A region of Cna directly on living bacteria without the need for labeling or purification. Some MAbs are more efficient in blocking single-cell adhesion, suggesting that they act as competitive inhibitors that bind Cna residues directly involved in ligand binding. This report highlights the role of protein mechanics in activating the function of staphylococcal adhesion proteins and emphasizes the potential of antibodies to prevent staphylococcal adhesion and biofilm formation. Cna is a collagen (Cn)-binding protein from Staphylococcus aureus that is involved in pathogenesis. Currently, we know little about the functional role of the repetitive B region of the protein. Here, we unravel the mechanical strength of Cna in living bacteria. We show that single Cna-Cn bonds are very strong, reflecting high-affinity binding by the collagen hug mechanism. We discovered that the B region behaves as a nanospring capable of sustaining high forces. This unanticipated mechanical response, not previously described for any staphylococcal adhesin, favors a model in which the B region has a mechanical function that is essential for strong ligand binding. Finally, we assess the antiadhesion activity of monoclonal antibodies against Cna, suggesting that they could be used to inhibit S. aureus adhesion.