Question

Researchers compared similar proteins from related organisms in different habitats. They found

that the proteins from organisms living in harsh environments had a greater number of cysteine
amino acids than did proteins from organisms not living in harsh environments. The structure of
cysteine is shown. Bonds can form between the sulfur atom of different cysteine amino acids (S-S bonds)
Which of the following best describes the effect of a greater number of cysteine amino acids on the
stability of the proteins?

Answer 1

The change leads to increased protein stability because of an increased number of S-S bonds in the tertiary structure of protein.

Step-by-step explanation:

Disulfide bond:

This is the bond in which sulfur of one amino acid forms a covalent bond with the sulfur of another amino acid.

Proteins contain normally two amino acids which have sulfur in their structure these are Methionine and cysteine

Disulfide bridges formation:

The disulfide bridges are formed by the oxidation of cysteine with the sulfhydryl groups. These bridges are important in the stabilization of the protein tertiary structure. These disulfide bridges are also responsible for bringing the hydrogen bonds closer in two parts of a chain.

Best Choice:

The change leads to increased protein stability because of an increased number of S-S bonds in the tertiary structure of a protein.