*3.2. Pore-Forming Activity of Porin M. primoryensis KMM 3633<sup>T</sup>*

It was found that the channels of MpOmp are characterized by a linear current-voltage characteristic and the dependence of conductivity on salt concentration. Purified porin reconstituted in BLM at a concentration 10–100 ng/mL induced stepwise changes in membrane conductance typical for porins. It is noteworthy that the activity of marine porins [17,18] as a rule, is lower (at 100–200 ng/mL) as compared to the activity of Enterobacteriaceae porins (at 1–10 ng/mL) [41].

Within the transmembrane potential of ±180 mV, MpOmp pores acted as ohmic channels, and their conductivity scaled linearly with voltage. Thus, the porin from *M. primoryensis* KMM 3633T behaves in a voltage-dependent manner, like the other marine porins [26,42].

It was shown that the pore-forming activity of the protein studied depends significantly on the ionic strength of the electrolyte. This is characteristic of the porins of marine bacteria. It is generally accepted that non-linear graphs of the dependence of the electrical conductivity of pores on the symmetric salt concentrations on both sides of the protein-containing membrane indicate the influence of the functionality of the internal channel on the passage of charged particles [26]. In the future we plan to build a theoretical protein model of MpOmp that will allow us to conduct a detailed analysis of charge distribution inside the barrel channel.
