Keratin and Silk: Structure, Bonds, and Function in Biological Tissues

What is the primary structural feature of keratin?

Rich in cysteine, resulting in many disulfide bonds.

What type of secondary structure is predominantly found in keratin?

Primarily α-helix coiled-coil.

What is the significance of disulfide bonds in keratin?

More disulfide bonds lead to stronger structures, such as hair and nails.

What is the repeating sequence in collagen?

Gly-X-Y, where X and Y are often proline and hydroxyproline.

What is the structural feature of silk?

Rich in glycine and alanine, with a repetitive sequence of Gly-Ala.

What type of secondary structure predominates in silk?

Predominantly β-sheets.

How does the structure of silk contribute to its properties?

High tensile strength and flexibility due to tight packing of β-sheets.

What stabilizes the structure of collagen?

Crosslinks between hydrophilic lysine and hydrogen bonds.

What is the composition of a typical keratin molecule?

A homodimer made of 300 amino acids.