Oscillating Electric Field Measures the Rotation Rate in a Native Rotary Enzyme

Abstract

Rotary enzymes are complex, highly challenging biomolecular machines whose biochemical working mechanism involves intersubunit rotation. The true intrinsic rate of rotation of any rotary enzyme is not known in a native, unmodified state. Here we use the effect of an oscillating electric (AC) field on the biochemical activity of a rotary enzyme, the vacuolar proton-ATPase (V-ATPase), to directly measure its mean rate of rotation in its native membrane environment, without any genetic, chemical or mechanical modification of the enzyme, for the first time. The results suggest that a transmembrane AC field is able to synchronise the steps of ion-pumping in individual enzymes via a hold-and-release mechanism, which opens up the possibility of biotechnological exploitation. Our approach is likely to work for other transmembrane ion-transporting assemblies, not only rotary enzymes, to determine intrinsic in situ rates of ion pumping.

Electromagnetic Stimulation of Microbial Activity in Wastewater Treatment: Experimental Equipment

“…Also, from the studies performed by the dielectric spectroscopy technique [50]- [52], it resulted that the stimulation takes place only at certain representative ("sensitive") frequencies. These results are in good agreement with the results of the in-depth studies reported [53].…”

The Energy Efficiency of Domestic Wastewater Treatment Processes: Case Analysis

“…The results of recent experimental investigations [41]- [44] suggest that the microbiological activity can also be stimulated by exposing biomass to an extremely low-frequency electromagnetic field (ELF). In this context, we propose the experimental development and implementation of a system to spur the biological treatment stages by exposing the biomass in the ELF field at a specific frequency, according to [41], [42], [54] at the wastewater treatment plant in Romuli.…”

Dielectric spectroscopic evaluation in the extremely low frequency range of an Aspergillus niger culture

“…It is noted that by overlapping an external EMF on the endogenous electric field of biological systems, the field resulting from the vectorial composition of these can influence (favourably or unfavourably) the cellular transport processes of molecules and electrons and, implicitly, the behaviour of the organism. In this context, the effect of a transmembrane AC field in the 1 Hz -10 kHz range on the biochemical activity of a native yeast vacuolar proton-ATPase (V-ATPase) had been reported recently [58], where the externally applied field generally inhibited the enzyme's rotational activity, except for a region peaking around 86 Hz, at which frequency, the field was able to synchronize the steps of ion-pumping in individual enzymes via a hold-and-release mechanism. It has been experimentally found that the 50 Hz electric field stimulates the growth and reproduction (production of spores) of Aspergillus niger [15].…”

“…This kind of behaviour could be attributed to different transmembrane ion-transporting proteinse.g. V-ATPase proton pumps, whose rotational rate can be determined by synchronizing the ion-pumping steps of individual enzymes with a transmembrane AC field [58]. Figure 2 shows the evolution of tgδ as function of frequency in the 1-60 Hz range (extension from Figure 1).…”