The chaperone activity of human αA-crystallin (HAA) against aggregation of human γD-crystallin (HGD) was enhanced by gold nanoparticles (AuNPs). Chaperone activity of HAA was almost doubled in the presence of 5.5 nM gold nanoparticles (AuNPs). To decipher this effect at molecular level, interactions between HAA and AuNPs were studied using fluorescence and circular dichroism spectroscopic techniques. The nanoparticles were synthesized and characterized by using TEM and dynamic light scattering (DLS). TEM and DLS studies revealed that bioconjugation of AuNPs with HAA did not cause any significant change in the size of the nanoparticles. AuNPs had caused static quenching of tryptophan (Trp) fluorescence, which was confirmed through determination of excited state lifetime of Trp residue of HAA in absence and the presence of AuNPs. The association and quenching constant for HAA-AuNPs conjugation were ∼ 10⁹ M⁻¹. Hydrogen bonding and van der Waals interactions were found to be involved in HAA-AuNPs complex. Polarity of Trp microenvironment in HAA was not perturbed by AuNPs as supported by synchronous and three-dimensional fluorescence spectroscopy. Far-UV CD spectra suggested that the secondary structure of HAA was not significantly affected by AuNPs.

金纳米粒子 (AuNPs) 增强了人 αA-晶状体蛋白 (HAA) 对人 γD-晶状体蛋白 (HGD) 聚集的伴侣活性。在 5.5 nM 金纳米粒子 (AuNPs) 存在下，HAA 的伴侣活性几乎翻了一番。为了在分子水平上破译这种效应，使用荧光和圆二色光谱技术研究了 HAA 和 AuNPs 之间的相互作用。通过使用 TEM 和动态光散射 (DLS) 合成和表征纳米颗粒。TEM 和 DLS 研究表明，AuNPs 与 HAA 的生物共轭不会导致纳米颗粒尺寸发生任何显着变化。AuNPs 引起了色氨酸 (Trp) 荧光的静态猝灭，这通过在不存在和存在 AuNPs 的情况下测定 HAA 的色氨酸残基的激发态寿命来证实。⁹ M ^-1。发现氢键和范德华相互作用与 HAA-AuNPs 复合物有关。在同步和三维荧光光谱的支持下，HAA 中 Trp 微环境的极性不受 AuNPs 的干扰。远紫外 CD 光谱表明 HAA 的二级结构不受 AuNPs 的显着影响。