Part:BBa_K3712000
a kind of elastin like peptide (VPGIG)27
USAGE AND BIOLOGY
It is a kind of elastin like peptide we designed. N means the number of VPGIG repeats. ELP (Elastin-like polypeptide) is a thermally responsive polymer that changes phase when it reaches a critical temperature. When the temperature is higher than the critical temperature, ELP will aggregate through hydrophobic action, and the hydrophobic tail will be surrounded in the interior while the hydrophilic head will be exposed. But ELP remains soluble below the critical temperature. ELP is composed of pentapeptide repeat sequence Val-Pro-Gly-Xaa-Gly (Xaa is any amino acid except Pro), and its transition temperature can be controlled by the concentration, the repeat number of ELP repeat sequence and the amino acid type at Xaa. Through theoretical prediction, we predict 10mg/L VPGIG27 aggregates at 42℃, which is the temperature used in acne heat treatment, so that heat treatment can combine with our drugs.
RESULTS
We use the ELP connected with the Wild-type BLP-7 for ELP functional verification. Under the temperature gradient of 30~50℃, the particle size measurement is carried out for every 1℃ increase. We find that the main peak of ELP aggregates distribution (more than 70%) gradually shifted to the larger particle size as the temperature increased. Location gathering. We averaged the main peaks of the three particle diameter measurements, and then plotted the average value as shown in Figure 1.A. We found that there is an inflection point at 44℃, which means that 44℃ is the transition temperature of Wild-type BLP-7-27 ELP. At the same time, we find that at 44℃ there is a rising inflection point for the Zeta potential, which is caused by rich positive charges of the Wild-type BLP-7 connected with the ELP aggregate.
Figure 1.A) The particle size of the ELP aggregate changes. The particle size is around 10 nm before 44℃, then it reaches 100 nm or more at 44℃, and thereafter it rises sharply. B) Changes in zeta potential of ELP aggregates. The change is relatively flat before 40℃, and the value is around -5mV; at 40℃, there is a sharp drop. That's because ELP has accumulated locally, but no aggregates are formed. The positive charge of ELP attracts anions in the solution environment, so it appears as a anionic enhancement; the inflection point appears at 43℃, where the ELP has been aggregated, and the relative density of the surface charge of the aggregate is lower than the charge density of the dispersed state. Therefore, the absolute value of the charge is reduced, but it will not cause electrical reversal and a particularly drastic change in the amount of charge occur.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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