EMF-Portal | Are the conformational dynamics and the ligand binding properties of myoglobin affected by exposure to microwave radiation?

Are the conformational dynamics and the ligand binding properties of myoglobin affected by exposure to microwave radiation? med./bio.

Aim of study (acc. to author)

To study the effects of microwaves on structural and functional properties of tuna myoglobin at 1.95 GHz, a frequency used by new wireless microwave communication systems.

Background/further details

In order to state safety guidelines it seems appropriate to start by excluding non-specific effects on dynamic and structural properties of fundamental biomolecules such as proteins (proteins are susceptible, in principle, to the action of electromagnetic fields).

Endpoint

structural and functional properties of myoglobin

Exposure

Exposure	Parameters
Exposure 1: 1.95 GHz Modulation type: CW Exposure duration: continuous for 2.5 h	SAR: 51 mW/g mean (± 1 mW/g) electric field strength: 197 V/m effective value

Exposure 1

Main characteristics

Frequency	1.95 GHz
Type	electromagnetic field
Exposure duration	continuous for 2.5 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	waveguide 110 x 55 x 500 mm, surrounded by a thermostated water jacket
Setup	The sample (3 ml of solution) in a polystyrene cuvette (10 x 10 x 35 mm) was placed vertically in the waveguide where the incident E field (vertical) was maximum.
Additional info	The sample temperature at the beginning was 25 ± 0.1 °C, it increased to 30 ± 0.1 °C in about 30 min, and it remained at that value for the rest of the exposure period.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	51 mW/g	mean	determined by power loss	-	± 1 mW/g
electric field strength	197 V/m	effective value	calculated	-	-

Measurement and calculation details

Power meters and sensors were used to measure the incident, reflected, and transmitted powers for determining the average SAR during the actual exposure. The SAR value was related to the electric field effective value by E = (ρ/σ)SAR^1/2 [Chou et al., 1996].

Reference articles

Chou CK et al. (1996): Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry

Exposed system:

isolated bio./chem. substance
myoglobin solution

Methods Endpoint/measurement parameters/methodology

Investigated system:

isolated bio./chem. substance
myoglobin solution

Time of investigation:

before exposure
after exposure

Main outcome of study (acc. to author)

The data indicate that, at least for the native state of the protein, microwave perturbation does not affect the structural organization of the myoglobin or its internal dynamics and CO binding affinity.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministero della Salute (Ministry of Health), Italy

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George DF et al. (2008): Non-Thermal effects in the microwave induced unfolding of proteins observed by chaperone binding

Mancinelli F et al. (2004): Non-thermal effects of electromagnetic fields at mobile phone frequency on the refolding of an intracellular protein: myoglobin