Hosseinzadeh Ghader, Maghari Ali, Farniya Seyed Morteza Famil, Keihan Amir Homayoun, Moosavi-Movahedi Ali A
Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
Mater Sci Eng C Mater Biol Appl. 2017 Aug 1;77:836-845. doi: 10.1016/j.msec.2017.04.018. Epub 2017 Apr 5.
Interaction of quantum dots (QDs) and proteins strongly influenced by the surface characteristics of the QDs at the protein-QD interface. For a precise control of these surface-related interactions, it is necessary to improve our understanding in this field. In this regard, in the present work, the interaction between the insulin and differently functionalized ZnS quantum dots (QDs) were studied. The ZnS QDs were functionalized with various functional groups of hydroxyl (OH), carboxyl (COOH), amine (NH), and amino acid (COOH and NH). The effect of surface hydrophobicity was also studied by changing the alkyl-chain lengths of mercaptocarboxylic acid capping agents. The interaction between insulin and the ZnS QDs were investigated by fluorescence quenching, synchronous fluorescence, circular dichroism (CD), and thermal aggregation techniques. The results reveal that among the studied QDs, mercaptosuccinic acid functionalized QDs has the strongest interaction (∆G=-51.50kJ/mol at 310K) with insulin, mercaptoethanol functionalized QDs destabilize insulin by increasing the beta-sheet contents, and only cysteine functionalized QDs improves the insulin stability by increasing the alpha-helix contents of the protein, and. Our results also indicate that by increasing the alkyl-chain length of capping agents, due to an increase in hydrophobicity of the QDs surface, the beta-sheet contents of insulin increase which results in the enhancement of insulin instability.
量子点（QDs）与蛋白质的相互作用在很大程度上受蛋白质 - 量子点界面处量子点表面特性的影响。为了精确控制这些与表面相关的相互作用，有必要加深我们对该领域的理解。在这方面，在本工作中，研究了胰岛素与不同功能化的硫化锌量子点（QDs）之间的相互作用。硫化锌量子点用羟基（OH）、羧基（COOH）、胺基（NH）和氨基酸（COOH和NH）等各种官能团进行功能化。还通过改变巯基羧酸封端剂的烷基链长度来研究表面疏水性的影响。通过荧光猝灭、同步荧光、圆二色性（CD）和热聚集技术研究了胰岛素与硫化锌量子点之间的相互作用。结果表明，在所研究的量子点中，巯基琥珀酸功能化的量子点与胰岛素的相互作用最强（在310K时∆G = -51.50kJ/mol），巯基乙醇功能化的量子点通过增加β - 折叠含量使胰岛素不稳定，而只有半胱氨酸功能化的量子点通过增加蛋白质的α - 螺旋含量提高了胰岛素的稳定性。我们的结果还表明，通过增加封端剂的烷基链长度，由于量子点表面疏水性增加，胰岛素的β - 折叠含量增加，从而导致胰岛素稳定性增强。
