title: Temperature-responsive mixed-shell polymeric micelles for the refolding of thermally denatured proteins.
abstract: We have fabricated a mixed-shell polymeric micelle (MSPM) that closely mimics the natural molecular chaperone GroEL-GroES complex in terms of structure and functionality. This MSPM, which possesses a shared PLA core and a homogeneously mixed PEG and PNIAPM shell, is constructed through the co-assembly of block copolymers poly(lactide-b-poly(ethylene oxide) (PLA-b-PEG) and poly(lactide)-b-poly(N-isopropylacryamide) (PLA-b-PNIPAM). Above the lower critical solution temperature (LCST) of PNIPAM, the MSPM evolves into a core-shell-corona micelle (CSCM), as a functional state with hydrophobic PNIPAM domains on its surface. Light scattering (LS), TEM, and fluorescence and circular dichroism (CD) spectroscopy were performed to investigate the working mechanism of the chaperone-like behavior of this system. Unfolded protein intermediates are captured by the hydrophobic PNIPAM domains of the CSCM, which prevent harmful protein aggregation. During cooling, PNIPAM reverts into its hydrophilic state, thereby inducing the release of the bound unfolded proteins. The refolding process of the released proteins is spontaneously accomplished by the presence of PEG in the mixed shell. Carbonic anhydrase B (CAB) was chosen as a model to investigate the refolding efficiency of the released proteins. In the presence of MSPM, almost 93 % CAB activity was recovered during cooling after complete denaturation at 70 °C. Further results reveal that this MSPM also works with a wide spectrum of proteins with more-complicated structures, including some multimeric proteins. Given the convenience and generality in preventing the thermal aggregation of proteins, this MSPM-based chaperone might be useful for preventing the toxic aggregation of misfolded proteins in some diseases.
authors.affiliation: Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, 300071, PR China.
authors.forename: Xue
authors.initials: X
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhenkun
authors.initials: Z
authors.lastname: Zhang
authors.forename: Fan
authors.initials: F
authors.lastname: Huang
authors.forename: Qian
authors.initials: Q
authors.lastname: Tao
authors.forename: Rujiang
authors.initials: R
authors.lastname: Ma
authors.forename: Yingli
authors.initials: Y
authors.lastname: An
authors.forename: Linqi
authors.initials: L
authors.lastname: Shi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007773:Lactates / Q000737:chemistry*; D008823:Micelles; D018832:Molecular Chaperones / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012996:Solutions; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D007773:Lactates; D008823:Micelles; D018832:Molecular Chaperones; D011108:Polymers; D011506:Proteins; D012996:Solutions; C088513:poly(lactic acid-ethylene glycol); C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols