Staphylococcus aureus expresses many Microbial Surface Recognizing Adhesive Matrix Molecules (MSCRAMM's) to recognize host extracellular matrix (ECM) molecules to initiate colonization. The MSCRAMM, fibronectin binding protein A (FnBPA), is an important adhesin for S. aureus infection. FnBPA also binds with fibrinogen (Fg) by using a unique ligand binding mechanism called dock, lock and latch. Nanoparticles, especially nanosilver particles have been widely used in a variety of biomedical applications which includes disease diagnosis and treatment, drug delivery and implanted medical device coating. In a biological system, when protein molecules encounter nanoparticle, they can be absorbed onto its surface which results in the formation of protein corona. In the present study, we have analysed the fibrinogen binding ability of rFnBPA(189-512) in the presence of silver nanoparticles by employing techniques like gel shift assay, Western blot, size exclusion chromatography, enzyme-linked immunosorbent assay, bio-layer interferometry and circular dichroism spectroscopy. The results indicate that rFnBPA(189-512) is unable to bind to Fg in the presence of a nanoparticle. This could be due to the inaccessibility of the Fg binding site and conformational change in rFnBPA(189-512). With nanoparticles, rFnBPA(189-512) undergoes significant structural changes as the β-sheet content has drastically reduced to 10% from the initial 60% at higher concentration of the nanoparticle. Pathogenic bacteria interact with its surrounding environment through their surface molecules which includes MSCRAMMs. Therefore MSCRAMMs play an important role when bacteria encounter nanoparticles. The results of the present study suggest that the orientation of the protein during the absorption on the surface of a nanoparticle as well as the concentration of the nanoparticle, will dictate the function of the absorbed protein and in this case the Fg binding property of rFnBPA(189-512).

中文翻译：

---

分析金黄色葡萄球菌表面粘附素FnBPA与纳米颗粒相互作用的粘附机制。

金黄色葡萄球菌表达许多微生物表面识别粘附基质分子（MSCRAMM's）以识别宿主细胞外基质（ECM）分子以启动定植。MSCRAMM，纤连蛋白结合蛋白A（FnBPA），是金黄色葡萄球菌感染的重要粘附素。FnBPA还通过使用称为对接，锁定和闩锁的独特配体结合机制与纤维蛋白原（Fg）结合。纳米颗粒，尤其是纳米银颗粒已被广泛用于各种生物医学应用中，包括疾病诊断和治疗，药物输送和植入的医疗器械涂层。在生物系统中，当蛋白质分子遇到纳米粒子时，它们可以被吸收到其表面上，从而形成蛋白质电晕。在目前的研究中，我们已经通过采用凝胶位移测定，蛋白质印迹，尺寸排阻色谱，酶联免疫吸附测定，生物层干涉法和圆二色光谱等技术分析了银纳米颗粒存在下rFnBPA（189-512）的纤维蛋白原结合能力。结果表明，在存在纳米颗粒的情况下，rFnBPA（189-512）无法与Fg结合。这可能是由于Fg结合位点不可及以及rFnBPA（189-512）中的构象变化。对于纳米颗粒，rFnBPA（189-512）发生了显着的结构变化，因为在更高的纳米颗粒浓度下，β-片层含量已从最初的60％急剧降低至10％。病原细菌通过其表面分子（包括MSCRAMM）与其周围环境相互作用。因此，当细菌遇到纳米颗粒时，MSCRAMM发挥着重要作用。本研究的结果表明，在纳米颗粒表面吸收过程中蛋白质的取向以及纳米颗粒的浓度将决定被吸收蛋白质的功能，在这种情况下将决定rFnBPA（ 189-512）。