Exon Exon Exon Figure 1: Resilin-Exons 1, 2 and 3 each comprise separate functio

Question

Exon Exon Exon Figure 1: Resilin-Exons 1, 2 and 3 each comprise separate functional protein domains. Exon 1 extends out of the cell into the extracellular space and exon 3 is intracellular. Exon 2 is a chitin binding domain, chitin being the major structural polysaccharide in the membrane that comprises the exoskeleton of insects. Its function is thus to anchor the extra- and intracellular subunits of resilin to the exoskeleton of insects. A. Exon 1, which extends outside of the cell membrane, contains 18 'elastic repeat units' (depicted as yellow disks in Figure 1) which are 15-mer repeats of these amino acids: GGRPSDSYGAPGGGN. These segments are attached by short (2-5) amino acid segments of opposite polarity to the 15-mer repeat units. Additionally, at the N- and C- terminus of this exon are larger segments that also have opposite polarity to the 15-mer repeat. In other words, the blue and yellow regions of exon 1 in the diagram above have opposite polarity. Exon 1, when studied in isolation, takes an extended conformation in water. In other words, it does not take any secondary structure but retains a mostly disordered structure. Upon heating, or removal of water, individual. exon 1 peptides begin to aggregate into stacks, as depicted below. Explain why the protein folds this way with and without water present. You should use your knowledge of amino acids to deduce the polarity of the 15-mer repeat and thus the polarity of the connecting regions. Consider glycine ambivalent in polarity neither polar nor nonpolar.

Explanation / Answer

Hydrophilic and hydrophobic interactions cause the protien to fold.The hydrophilic amino acids interact more strongly with water than the hydrophobic amino acid.

Water soluble priteins fold into compact structures with non polar hydrobhobic cores..that are normally allowed to deduce the structure of single conformative native protein.

Protein folding is also known as denaturation .

In foldibg you have comptition between given residue interacting with other residue inthe protein

Aliphatic R groups are non polar and hydrophobic Hydrophobicity increases with increase in number of C atoms in hydrocarbon chain .although these amino acid remain inside the protein .glycine is ambivalent because it can be present both inside and outside the protein .

Another example of ambivalent amino acid is alanine

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.