Elastin-like polypeptides (ELPs) consist of simple pentapeptide repeats which can be easily modified by substituting various amino acid residues to control its properties. This provides an ideal platform for studying hydrophobic collapse and secondary/tertiary structure formation. In this thesis, the collapse process of ELP was studied with differential scanning calorimetry (DSC). In DSC thermal cycling, a clear conformational transition was observed. Also, a transiently stable state of ELP V5-120 was noted and it was found that the formation of this state was related to temperature, ramping rate and stabilization time. To explain this, a conformational redistribution model is proposed in which there are two conformations in the ELP solution below its transition temperature. However, after the system is heated up and cooled back down, one of the conformations remains the same while the other one changes to two new conformations. After the conformational distribution is done, the ELP stays in a transiently stable state before gradually shifting back to the original, pre-heat-treatment state. Bi-Gaussian fitting was used to fit DSC response curve and monitor the changes of the different conformations in the system. The influence of ramping rate on the process of conformational redistribution was explained through the equilibration time at each temperature point through heating and cooling. Overall, the ELP V5-120 system is in a dynamic conformational equilibrium, and the equilibration time is much longer than earlier expectations.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/148149 |
| Date | 14 March 2013 |
| Creators | Zhou, Qian |
| Contributors | Cremer, Paul |
| Source Sets | Texas A and M University |
| Detected Language | English |
| Type | Thesis, text |
| Format | application/pdf |
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