Complexation of Lysozyme with Sodium Poly(styrenesulfonate) via the Two-State and Non-Two-State Unfoldings of Lysozyme.
To provide an in-depth understanding of the complexation mechanism of protein and polyelectrolyte, a heating-cooling-reheating protocol was employed to study the unfolding and refolding behaviors of a model protein, lysozyme, in the presence of a negatively charged polyelectrolyte, sodium poly(styrenesulfonate) (PSS). It was found that, with elevated PSS concentration, a new state (state I) was first formed via a "two-state" conversion process and this state could further convert to a completely unfolded state (state II) via a "non-two-state" conversion. This non-two-state conversion process occurs without the coexistence of states I and II but involves the formation of various intermediate unfolded protein structures. Different from the pure lysozyme that exhibited refolding upon cooling from its heat-denatured state, lysozyme in state I could undergo unfolding upon heating but no refolding upon cooling, while lysozyme in state II did not undergo unfolding or refolding upon thermal treatments. In addition, the effects of ionic strength and molecular weight of polyelectrolyte on the unfolding and refolding behaviors of lysozyme were also investigated. The present work provides a better understanding of the principles governing protein-polyelectrolyte interactions and may have implications for the fabrication of biocolloids and biofilms.
Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University , Beijing 100084, People's Republic of China.|State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, People's Republic of China.
Fu-Gen
FG
Wu
State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, People's Republic of China.
Yao-Wen
YW
Jiang
Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University , Beijing 100084, People's Republic of China.
Hai-Yuan
HY
Sun
Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University , Beijing 100084, People's Republic of China.
Jun-Jie
JJ
Luo
Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University , Beijing 100084, People's Republic of China.
Zhi-Wu
ZW
Yu
D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D046529:Microscopy, Electron, Transmission; D009113:Muramidase / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D058767:Protein Unfolding; D013056:Spectrophotometry, Ultraviolet
D011137:Polystyrenes; C003321:polystyrene sulfonic acid; D009113:Muramidase