1) Polyaspartate, (Asp)n,forms regions of a helices in aqueous solutions below pH 3.0, but above pH 5.0, it assumes an extended conformation.
b) At what pH would polylysine, (Lys)n,be likely to form a helix?
b) Tryptophan is the residue least often replaced without loss of protein function.
c) Changes such as Lys->Arg and Ile->Leu often have little effect on protein function.
d) Glycine residues are often conserved at certain positions within protein chains despite evolutionary changes at other positions.
4) Why is proline frequently found at the places where the polypeptide chain turns over in both hemoglobin and myoglobin?
5) What is the difference between hair and silk at the molecular level? How does this difference give rise to the fact that hair stretches more easily than silk does?
6) List two similarities and two differences in the structures between hemoglobin and myoglobin.
7) A number of mutant hemoglobins, in addition to HbS, have single amino acid residue replacements in either the a or b chain. In a mutant hemoglobin known as Hb Providence, an asparagine residue replaces Lys b-EF6 which projects into the central cavity of the tetrameric protein.
b) What effect would this mutation have on the oxygenation of Hb providence?
Problem #1