To identify genes coding for essential proteins, researchers can create temperature-sensitive mutations. These mutations allow proper protein folding and cell proliferation at the permissive temperature of 22ºC, but they cause protein misfolding and reduced cell proliferation at a higher restrictive temperature, such as 37ºC. Which of the following mutations might increase protein flexibility and lead to a temperature-sensitive phenotype?

Question

A.) mutation of a lysine (that was involved in an ionic bond with a glutamic acid) to a glycine
B.) mutation of a bulky isoleucine that was buried in the protein interior to a glycine (side chain=H)
C.) mutation of a alanine to a cysteine, leading to the formation of a new disulfide bond

Answer 1

Ans:
A.) mutation of a lysine (that was involved in an ionic bond with a glutamic acid) to a glycine
B.) mutation of a bulky isoleucine that was buried in the protein interior to a glycine (side chain-H)