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Updated: Sep 28, 2026

PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions
Published on: July 27, 2017
The effects of protein hydrophobic exposure on the slope of the line in the deltapi vs pi(i) plot
Fan Zhang1, Ying-Jie Lu, Shao-Xiong Wang
1Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, People's Republic of China.
Abstract:
The deltapi vs pi(i) curve from monolayer surface pressure detection is a powerful method to characterize the membrane insertion. The deltapi vs pi(i) curve is fixed by two parameters, the pi(c) and the slope. The intersected point (pi(c)) of deltapi vs pi(i) curve with abscissa is generally used as a quantitative measure of the membrane insertion ability of a protein. In the current work we demonstrate a correlation between the variation in the slope of the deltapi vs pi(i) curve with protein hydrophobic exposure by performing monolayer experiments on three different proteins, human apolipoprotein H, trichosanthin, and mutant trichosanthin. The value of /slope/ increases gradually following the degree of hydrophobic exposure. These findings suggest that the two parameters, the pi(c) and the slope, will complement each other to interpret the lipid/protein interaction involved in membrane insertion.
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