ABSTRACT The question of possible health risks related to microwave electromagnetic fields (MWEMF) exposure caused by mobile phones usage has produced, in about two decades, a huge experimental work, which varies a lot either in the choice of exposure device and protocol, and in the investigated biological system; for this reason, definitive conclusions are still matter of debate. Our group is working for years about possible non-thermal effects of MWEMF on tuna apomyoglobin molecules. This well-known protein present a bulk of spectroscopic observables, which make it very suitable for studying, in particular, its conformational dynamics. Preliminarly, we have checked whether exposure to low powered MWEMF causes loss of secondary structure and function capability of apomyoglobin in solution, observed by molecular absorption and circular dichroism, as well as changes in its conformational dynamics analyzed by measurements of fluorescence lifetime of apomyoglobin sole tryptophan residue; no remarkable effects have been found in this situation. Afterwards, following the hypothesis that a better candidate to undergo changes in some of its properties due to an external electromagnetic perturbation is a partially refolded structure, we have studied possible non-thermal MWEMF effects on apomyoglobin in its acidic state: in this case, an alteration in the refolding process has been observed, together with a different population of the conformational substates among which the protein fluctuate. The alteration in the refolding process could have repercussions on the competent aggregation process, with formation of amorphous oligomers which could resonate even more at MWEMF frequencies. This conjecture seems to be addressed by computational studies we have carried out about apomyoglobin conformational dynamics, which show how the widest backbone motions frequencies of small oligomers fall in the range of microwaves. All these results would open a very interesting landscape, since many modern social diseases are caused by misfolding/aggregation processes.
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