4. Elastin, a muscle fiber protein, can assemble into fibers and disassemble depending on temperature. It assembles at higher temperatures and disassembles at lower temperatures. At higher temperatures, the change in free energy for the reaction, elastin --> elastin fibers, is negative for the reaction to proceed. Conversely, the free energy is positive at lower temperatures to allow for elastin fiber disassembly. Decide what the signs of the change in enthalpy and the change in entropy need to be. Explain how your choices account for the assembly of elastin at high temperature and its disassembly at low temperature. Assume that the change in enthalpy and the change in entropy are constant over this temperature range.
3. Consider the following protein sequence as an α helix: Leu-Lys-Arg-Ile-Val-Asp-Ile-LeuSer-Arg-Leu-Phe-Lys-Val. How many turns does this helix make? Do you notice anything interesting about the arrangement of the amino acids when folded into an α helix? Explain.
4. Elastin, a muscle fiber protein, can assemble into fibers and disassemble depending on temperature. It assembles at higher temperatures and disassembles at lower temperatures. At higher temperatures, the change in free energy for the reaction, elastin --> elastin fibers, is negative for the reaction to proceed. Conversely, the free energy is positive at lower temperatures to allow for elastin fiber disassembly. Decide what the signs of the change in enthalpy and the change in entropy need to be. Explain how your choices account for the assembly of elastin at high temperature and its disassembly at low temperature. Assume that the change in enthalpy and the change in entropy are constant over this temperature range.
3. Consider the following protein sequence as an α helix: Leu-Lys-Arg-Ile-Val-Asp-Ile-LeuSer-Arg-Leu-Phe-Lys-Val. How many turns does this helix make? Do you notice anything interesting about the arrangement of the amino acids when folded into an α helix? Explain.
Related textbook solutions
Related questions
For each polypeptide sequence, indicate what characteristic(s)an α helix or β sheet secondary structure
would have upon folding. The polar amino acids are italicizedand in bold.
| Polypeptide sequence | If folded into an α helix: | If folded into a β sheet: |
| Leu-gly-val-leu-gly-leu-phe-phe-gly-leu-met-trp-phe-phe-trp-ile | ||
| Ile-gln -lys-pro-thr-ser -asn-trp-asp -glu -ile-his -lys-arg -met-his | ||
| Thr -leu-asn-ile-ser-phe-gln -met-glu-leu-asp-val-ser-ile-arg -trp |
