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Map pling a-Keratin is an intermediate filament with a basic structural unit of

ID: 52869 • Letter: M

Question

Map pling a-Keratin is an intermediate filament with a basic structural unit of two a helices in a coiled coil. Each helix has a seven residue repeating unit (heptad repeat). A representation looking down the a helices of a coiled coil dimer is shown below. Each letter represents a different amino acid residue. Identify the three true statements about the structure of keratin. Click here to view a table of the amino acids. at positions b and care less likely to be polar or charged because they are in contact with the solvent. Val-Lys-Asn-Ala-Arg-Glu-Asn is a likely repeat in the a helix of keratin. The ahelix of the coiled coil is wound less tightly than predicted for an a helix. Each polypeptide in the dimer has 3.6 residues per turn, and a nonpolar group occurs every 3.5 residues, resulting in a slight winding, or twist, around the other polypeptide, forming a coiled coil. a Keratin is rich in Cys residues, enabling the formation of covalent cross nks between peptide chains and increasing the strength of the protein. Glu-Ala-Asn-Arg-Asn-Lys-GIn is a likely repeat in the a helix of keratin. Keratin molecules are very strong due to hydrophilic interactions between charged amino acid side chains

Explanation / Answer

The answers are

Each polypeptide in the dimer has 3.6 residues per turn......

Glu-Ala-Asn-Arg-Asn-Lys-Gln is a likely repeat in the alpha helix of Keratin.

The alpha helix of the coiled coil is wound less tightly than predicted for an alpha helix