You have just sequenced a new protein found in mice and obse

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals What is the significance of this finding? It will be important to include cysteine in the diet of the mice. Cysteine residues are required for the formation of alpha-helices and beta-pleated sheets Cysteine residues are involved in disulfide bridges that help form tertiary structure Cysteine causes bends or angles to occur in the tertiary structure of proteins

Solution

Answer: Cystein residues are involved in disulfide bridges that help form tertiary structures.

Disulfide bridges are most prominant covalent bonds in tertiary structures found in many extra cellular proteins. Cystein has a thiol group that is unique among the 20 amino acids in that it often forms a disulfide bond to another cystein residue through the oxidation of their thiol groups. This dimeric compound is reffered to as the amino acid cystine.