The amino acid sequences below are found in an a-helix in the proteins below, as described. Match the protein to the helix. Only one of the sequences is not found as an a-helix at pH 7.
A: Val-Val-Ala-Gly-Val-Ala-Leu-Ala-Leu-Ala a. ____ at the surface of a water-soluble protein
B: Ala-Leu-Glu-Leu-Phe-Arg-Ile-Val-Met-Gln b. ____ a single helix that spans a biomembrane
C: Ser-Lys-Asn-Glu-Thr-Gln-His-Gly-Ser-Arg c. ____ a helix completely surrounding by water
D: Val-Glu-Asp-Pro-Asp-Gly-His-Lys-Pro-Arg d. ____ this sequence cannot be an a-helix
