Temperature dependent mistranslation in a hyperthermophile adapts proteins to lower temperatures

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Organisms require proteins that function optimally within specific environmental conditions.
• Environmental fluctuations can challenge the stability and function of cellular proteins.
• Hyperthermophilic archaea like Aeropyrum pernix exhibit remarkable temperature adaptability, but the underlying mechanisms are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms enabling Aeropyrum pernix to adapt to a wide range of growth temperatures.
• To determine if protein synthesis fidelity is altered under varying temperature conditions.
• To explore the functional consequences of mistranslation on protein activity at low temperatures.

Main Methods:

• Investigated tRNA misacylation by methionyl-tRNA synthetase (MetRS) in A. pernix at different temperatures.
• Analyzed the charging fidelity of tRNA(Leu) by MetRS under varying thermal conditions.
• Compared the low-temperature activity of citrate synthase produced via mistranslation versus high-fidelity synthesis.

Main Results:

• A. pernix exhibits constitutive leucine to methionine mistranslation at low growth temperatures.
• The A. pernix MetRS shows temperature-dependent shifts in tRNA charging fidelity, misacylating tRNA(Leu) with methionine at lower temperatures.
• Citrate synthase synthesized during low-temperature mistranslation demonstrates enhanced activity compared to its high-temperature synthesized counterpart.

Conclusions:

• Conditional mistranslation, specifically leucine to methionine, can enhance the low-temperature activity of hyperthermophilic proteins.
• This mistranslation likely increases protein flexibility, improving function at reduced physiological temperatures.
• Mistranslation represents a novel adaptive strategy for extremophilic organisms to cope with environmental variability.