For 10 points, name this only achiral amino acid, whose side chain is a hydrogen atom.
It's not serine, but hydrogen bonding between this amino acid at position 193 and an oxygen atom in the oxyanion hole stabilizes the tetrahedral intermediate in both the acylation and deacylation steps in the mechanism of chymotrypsin. Serine is biosynthesized from this amino acid to form NADH and carbon dioxide during photorespiration. Repeats consisting of this amino acid, alanine, and serine in a 3:2:1 ratio comprise much of the structure of silk fibroin. This amino acid and proline are rarely found in (*) alpha-helices. This amino acid is found in type II beta-turns due to its high flexibility caused by its low steric bulk. This amino acid comprises about one-third of the amino acids in collagen. For 10 points, name this only achiral amino acid, whose side chain is a hydrogen atom.
It's not serine, but hydrogen bonding between this amino acid at position 193 and an oxygen atom in the oxyanion hole stabilizes the tetrahedral intermediate in both the acylation and deacylation steps in the mechanism of chymotrypsin.
glycine [accept Gly or G]