What structural difference between gram-negative and gram-positive bacterium makes one more susceptible than the other when exposed to high temperature?

Both have similar structures so they react similarly when exposed to high temperatures

Gram-positive has a thin peptidoglycan layer that gets easily disrupted by high temperature

Gram-negative has an extra protective layer that shields it from high temperature

Gram-negative has a thin peptidoglycan layer which gets easily disrupted under high temperature