posted by Big Mark .
I'm supposed to pick three that are true, and my personal guesses are 2, 3 and 6. I'd love to know if these are right and if so, why are they right. If not, could someone possibly lead me in the right direction?
1. Leu-Glu-His-Val-Cys-Lys-Ser is a likely repeat in the α helix of keratin.
2. Each polypeptide in the dimer has 3.5 residues per turn, resulting in the slight winding, or twist, around the other polypeptide, that helps form the coiled coil.
3. The residues at positions b and c are less likely to be polar or charged because they are in contact with the solvent.
4. Keratin molecules are very strong due to hydrophilic interactions between charged amino acid side chains.
5. Lys-Val-Ser-Cys-Ser-Glu-Thr is a likely repeat in the α helix of keratin.
6. The α helix of the coiled coil is wound less tightly than predicted for an α helix.
7. α-Keratin is rich in Cys residues, enabling the formation of covalent cross-links between peptide chains and increasing the strength of the protein.