My protease has a globular structure with beta sheets alpha

My protease has a globular structure with beta sheets, alpha helix and many sharp turns. It has a pocket where it binds amino acids and it has a flexible hinge that is regulated to cover the pocket so the enzyme can be turned off. Match the amino acid to the MOST APPROPRIATE location in/on the enzyme.

open hinge    closed hinge

proline

glycine

histidine

phenylalanine

serine

none of these

a sharp fixed turn in the protein backbone

a flexible hinge

the active site

internal within the enzyme

external on the enzyme

Solution

cysteine - the active site

proline - a sharp fixed turn in the protein backbone

glycine - a flexible hinge

histidine - none of these

phenylalanine - internal within the enzyme

serine - external on the enzyme

histidine is used to activate cysteine and threonine on proteases so that it would function.

the built-in bend in proline and lack of large side chain in glycine allow the protein to fold into a tight U-shape.

since phenylaanine is hydrophobic, it is buried inside the globular protein.

serine is hydrophilic.