Porin from Marine Bacterium Marinomonas primoryensis KMM 3633T: Isolation, Physico-Chemical Properties, and Functional Activity

Adaptation Potential of Three Psychrotolerant Aquatic Bacteria in the Pan-Okhotsk Region

The Pan-Okhotsk region, which is part of the western North Pacific Ocean, is famous for its active volcanoes, which are part of the Pacific Ring of Fire and that enrich the surrounding waters with essential chemicals. Therefore, this region, including the Sea of Okhotsk and the Sea of Japan, is characterized by rich biota. Bacterioplankton plays a significant part in biological communities and is an indicator of ecosystem function. Analyzing the adaptability of three representatives of the microbiota of the Pan-Okhotsk region was the goal of our investigation. Marinomonas primoryensis KMM3633T (MP), Yersinia ruckeri KMM821 (YR), and Yersinia pseudotuberculosis 598 (YP) from the G.B. Elyakov Pacific Institute of Bioorganic Chemistry were studied by means of genomic and bioinformatic methods. The list of membrane translocator proteins, metabolism pathways, and cold shock and antifreeze proteins that were revealed in the genome of MP characterized this bacterium as being adaptable to free living in marine conditions, even at winter temperatures. The genomic potential of YR and YP makes not only survival in the environment of the Pan-Okhotsk region but also pathogenesis in eukaryotic organisms possible. The data obtained will serve as a basis for further ecosystem monitoring with the help of microbiota research.

Non-specific porins of Gram-negative bacteria as proteins containing intrinsically disordered regions with amyloidogenic potential

Features of the structure and functional activity of bacterial outer membrane porins, coupled with their dynamic "behavior," suggests that intrinsically disordered regions (IDPRs) are contained in their structure. Using bioinformatic analysis, the quantitative content of amyloidogenic regions in the amino acid sequence of non-specific porins inhabiting various natural niches was determined: from terrestrial bacteria of the genus Yersinia (OmpF and OmpC proteins of Y. pseudotuberculosis and Y. ruckeri) and from the marine bacterium Marinomonas primoryensis (MpOmp). It was found that OmpF and OmpC porins can be classified as moderately disordered proteins, while MpOmp can be classified as highly disordered protein. Mapping of IDPRs, performed using 3D structures of monomers of the proteins, showed that the regions of increased conformational plasticity fall on the regions, the functional importance of which has been reliably confirmed as a result of numerous experimental studies. The revealed correlation made it possible to explain the differences in the physicochemical characteristics and properties of not only porins from terrestrial and marine bacteria, but also non-specific porins of different types, OmpF and OmpC proteins. First of all, this concerns the flexible outer loops that form the pore vestibule, as well as regions of the barrel with an increased "ability" for aggregation, the so-called "hot spots" of aggregation. The abnormally high content of IDPRs in the MpOmp structure made it possible to suggest that the high adaptive potential of bacteria may correlate with an increase in the number of IDPRs and/or regions with increased conformational variability.