Event Information
HYDROPHOBIC INTERACTIONS AT A SINGLE MOLECULE LEVEL: FORCE SPECTROSCOPY STUDY OF INTERACTIONS BETWEEN ALKANES AND BETWEEN FRAGMENTS OF -SYNUCLEIN
- Abstract:
The kinetics of hydrophobic interactions is poorly understood and difficult to measure experimentally because aggregation and solubility problems preclude spectroscopic and scattering based approaches. AFM based single molecule force spectroscopy can overcome these issues. Force spectroscopy determines kinetic parameters of dissociation between molecules from the statistical analysis of rupture forces between molecules understudy. The interacting molecules are aided into solution without changing the chemical environment by “mechanical” solubilization. Statistical analysis of the rupture forces reveals kinetic parameters, including the dissociation rate and the distance from the equilibrium to the transition state (often called the barrier width). These parameters are often difficult (and even impossible) to measure using other physico-chemical techniques. It is noted that the standard force spectroscopy data analysis methodology results in considerable systematic errors in the kinetic parameters. Systematic error correction has been developed and implemented to enable the comparison of data collected with different tip-sample pairs, and to make the data easier to compare both with other data in the field, as well as with data collected using other experimental techniques. The developed approach has been applied to both alkane (hexadecane and octadecane are presented here) and hydrophobic peptide (a-synuclein hydrophobic core peptide) systems to clarify the role of hydrophobic interactions in these systems and to compare the experimentally measured parameters with recent theoretical predictions, including the prediction of decreased water density at hydrophobic interfaces with sizes of approximately 1-nm.
Ph.D. Defense Examination Seminar
Student Exams Seminar