Engineered Synthetic Polymer Nanoparticles as IgG Affinity Ligands
详细信息 查看全文
- 作者：Shih-Hui Lee ; Yu Hoshino ; Arlo Randall ; Zhiyang Zeng ; Piere Baldi ; Ruey-an Doong ; Kenneth J. Shea
- 刊名：The Journal of the American Chemical Society
- 出版年：2012
- 出版时间：September 26, 2012
- 年：2012
- 卷：134
- 期：38
- 页码：15765-15772
- 全文大小：443K
- 年卷期：v.134,no.38(September 26, 2012)
- ISSN：1520-5126
文摘
A process for the preparation of an abiotic protein affinity ligand is described. The affinity ligand, a synthetic polymer hydrogel nanoparticle (NP), is formulated with functional groups complementary to the surface presentation of the target protein. An iterative process is used to improve affinity by optimizing the composition and proportion of functional monomers. Since the polymer NPs are formed by a kinetically driven process, the sequence of functional monomers in the polymer chain is not controlled; only the average composition can be adjusted by the stoichiometry of the monomers in the feed. To compensate for this the hydrogel NP is lightly cross-linked resulting in chain flexibility that takes place on a submillisecond time scale allowing the polymer to 鈥渕ap鈥?onto a protein surface with complementary functionality. In this study, we report a lightly cross-linked (2%) N-isopropyl acrylamide (NIPAm) synthetic polymer NP (50鈥?5 nm) incorporating hydrophobic and carboxylate groups that binds with high affinity to the Fc fragment of IgG. The affinity and amount of NP bound to IgG is pH dependent. The hydrogel NP inhibits protein A binding to the Fc domain at pH 5.5, but not at pH 7.3. A computational analysis was used to identify potential NP鈥損rotein interaction sites. Candidates include a NP binding domain that overlaps with the protein A鈥揊c binding domain at pH 5.5. The computational analysis supports the inhibition experimental results and is attributed to the difference in the charged state of histidine residues. Affinity of the NP (3.5鈥?.5 nM) to the Fc domain at pH 5.5 is comparable to protein A at pH 7. These results establish that engineered synthetic polymer NPs can be formulated with an intrinsic affinity to a specific domain of a large biomacromolecule.