Genetically engineered silk-elastin-like proteins (SELPs) combining the physical and biological properties of silk and elastin have potential for use in various biomaterial-related applications, such as controlled drug delivery and gene therapy.  To obtain improved insight into the self-assembly kinetics and tuning of the inverse transition temperature (ITT) of these protein polymers, a family of SELPs patterned after B. mori silkworm silk (GAGAGS) and mammalian elastin (GYGVP or GVGVP), with or without a his-tag, were synthesized using recombinant DNA technology.  Temperature-dependent circular dichroism and Fourier transform infrared spectroscopy were used to assess changes in secondary structure during heating and cooling.  Thermal properties were determined by differential scanning calorimetry.  The results indicated that the ITT of SELPs can be adjusted based on the silk to elastin ratio and the presence of the his-tag. Silk to elastin block ratios of 1:8 and 1:4, had an ITT from 27 to 42oC; while a silk block to elastin block ratio of 1:2 did not possess a thermal response.  The ITT was increased about 5oC with the his-tag present for the 1:8 and 1:4 variants, because of the hydrophilic nature of the his-tag.  The results suggest that the ITT of SELPs can be coarsely tuned by the silk to elastin ratio, and further fine-tuned by the his-tag.  These insights should help refine SELP designs to match specific target applications.This work is supported by NIH (P41 EB002520).

Role of his-tag on self-assembly of silk-elastin-like proteins

247th National Meeting (2014)

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