Luo Lei, Liu Yuan-Yuan, Gao Tiange, Wang Xinping, Chen Jingqi, Wang Haifang, Liu Yuanfang, Cao Aoneng
Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, China.
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
ACS Appl Mater Interfaces. 2020 Aug 5;12(31):34514-34523. doi: 10.1021/acsami.0c05994. Epub 2020 Jul 28.
The interaction between nanoparticles and proteins is a central problem in the nano-bio-fields. However, it is still a great challenge to characterize the specific interaction between nanoparticles and proteins in structural details. Using the Goldbodies, the artificial antibodies created by grafting complementary-determining regions (CDRs) of natural antibodies onto gold nanoparticles, as the models, we manage to identify the key residues of the CDR peptides on gold nanoparticles for the specific interactions by alanine scanning mutagenesis. Each and every residue of the CDR peptides on two Goldbodies (which specifically bind with hen egg white lysozyme and epidermal growth factor receptor, respectively) is mutated to alanine one by one, generating a total of 18 single-mutants of the two Goldbodies. Experimental results reveal that the key residues of the CDR peptides for the specific interactions between the two Goldbodies and the corresponding antigens are exactly the same as those in the natural antibodies, thus proving that the correct conformations of the CDRs of natural antibodies have been successfully reconstructed on AuNPs. This is the first residue-resolution structural illustration for the specific interaction between a designed nanoparticle and a protein.
纳米颗粒与蛋白质之间的相互作用是纳米生物领域的核心问题。然而，在结构细节上表征纳米颗粒与蛋白质之间的特定相互作用仍然是一个巨大的挑战。我们以金体（通过将天然抗体的互补决定区（CDR）嫁接到金纳米颗粒上而产生的人工抗体）为模型，通过丙氨酸扫描诱变成功鉴定了金纳米颗粒上CDR肽段中参与特异性相互作用的关键残基。对分别与鸡蛋清溶菌酶和表皮生长因子受体特异性结合的两种金体上CDR肽段的每个残基逐一突变为丙氨酸，共产生了两种金体的18个单突变体。实验结果表明，两种金体与相应抗原特异性相互作用的CDR肽段的关键残基与天然抗体中的完全相同，从而证明天然抗体CDR的正确构象已在金纳米颗粒上成功重建。这是首次对设计的纳米颗粒与蛋白质之间的特异性相互作用进行残基分辨率的结构阐释。
