In keratin, cross-links stabilizing quarternary structure are disulfidebonds.
How can fibrous proteins strength be enhanced? By covalentcross-links
Collagen is left-handed and has 3 amino acid residues per urn.
Gelatin is derived from collagen
Collagen contains a lot of proline and glycine residues.
Proline permits the sharp twisting in collagen.
As you get older, connective tissue becomes more rigid and brittle dued to accumulated covalent cross-links.
Silk fibroin is rich in alanine and glycine residues.
Silk does not stretch, because the B conformation is already highly extended.
A loss of 3-D structure that causes loss of function is called denaturation.
Circular dichroism measures the amount of helical structure in a protein.
Urea disrupts hydrogen bonds.
Organic solvents, urea, and detergents disrupt hydrophobic aggregation of nonpolar amino acid side chains, which produces the stable core of globular proteins.
Extremes of pH alter the net charge on a protein, causing electrostatic repulsion and the disruption of some hydrogen bonding.
Protein precipitation is a consequence of protein aggregate formation as exposed hydrophobic surfaces associate.
Unfolded states have a high degree of conformational entropy and high free energy.
Chaperones facilitate correct folding
Peptide C-N bonds have partial double bond character, meaning they cannot rotate freely.
B turns connect the ends of two adjacent segments of antiparallel B sheets.
Glycine and Proline are often found in B-Turns.
The light-absorbing entity is also referred to as chromophore.