Microwave radiation can alter protein conformation without bulk heating

Area of Science:

• Biophysics
• Cellular Biology
• Biochemistry

Background:

• Microwave radiation exposure is increasingly common.
• Previous studies suggested non-thermal effects of microwaves on biological systems.
• The impact of microwave radiation on protein structure and cellular responses requires further investigation.

Purpose of the Study:

• To investigate the effects of microwave radiation on protein aggregation in vitro.
• To determine if microwave exposure induces cellular heat-shock responses.
• To elucidate the role of heat-shock factor in mediating these responses.

Main Methods:

• In vitro aggregation assays of bovine serum albumin and bovine insulin.
• Exposure to controlled microwave radiation.
• Measurement of specific absorbed radiation using field modeling.
• Induction of heat-shock responses in Caenorhabditis elegans.
• RNA interference to ablate heat-shock factor function.

Main Results:

• Microwave radiation exposure enhanced bovine serum albumin aggregation in a time- and temperature-dependent manner.
• Microwave radiation promoted amyloid fibril formation in bovine insulin at 60°C.
• Observed protein conformational changes occurred without significant temperature increases, aligning with modeled specific absorbed radiation.
• Microwave exposure induced modest heat-shock responses in Caenorhabditis elegans.
• Heat-shock responses to both heat and microwaves were diminished following heat-shock factor gene silencing.

Conclusions:

• Microwave radiation can induce non-thermal protein aggregation and amyloid formation in vitro.
• These protein alterations may contribute to cellular stress responses, such as heat-shock responses.
• Heat-shock factor plays a role in mediating cellular responses to microwave-induced stress.