No abstract

The newly obtained chimeric antigen could be valuable for the development of the preventing tick-borne encephalitis subunit vaccines.

The encoding sequence of the pore-forming OmpF-like protein from the Yersinia pseudotuberculosis outer membrane was cloned and expressed in Escherichia coli cells. Conditions were selected for isolation and refolding of recombinant monomer and porin trimer. Their spatial structures were characterized by the intrinsic protein fluorescence and CD spectroscopy. It was shown that the recombinant porins are similar in the composition of secondary structure elements to the isolated porins, but have a considerably less compact tertiary structure. The pore-forming activities of the recombinant proteins are similar to those of Y. pseudotuberculosis native porins. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru.

No abstract

A novel OmpY porin was predicted based on the Yersinia pseudotuberculosis genome analysis. Whereas it has the different genomic annotation such as "outer membrane protein N" (ABS46310.1) in str. IP 31758 or "outer membrane protein C2, porin" (YP_070481.1) in str. IP32953, it might be warranted to rename the OmpN/OmpC2 to OmpY, "outer membrane protein Y", where letter "Y" pertained to Yersinia. Both phylogenetic analysis and genomic localization clearly support that the OmpY porin belongs to a new group of general bacterial porins. The recombinant OmpY protein with its signal sequence was overexpressed in porin-deficient Escherichia coli strain. The mature rOmpY was shown to insert into outer membrane as a trimer. The OmpY porin, isolated from the outer membrane, was studied employing spectroscopic, electrophoretic and bilayer lipid membranes techniques. The far UV CD spectrum of rOmpY was essentially identical to that of Y. pseudotuberculosis OmpF. The near UV CD spectrum of rOmpY was weaker and smoother than that of OmpF. The rOmpY single-channel conductance was 180 ± 20 pS in 0.1 M NaCl and was lower than that of the OmpF porin. As was shown by electrophoretic and bilayer lipid membrane experiments, the rOmpY trimers were less thermostable than the OmpF trimers. The porins differed in the trimer-monomer transition temperature by about 20°C. The three-dimensional structural models of the Y. pseudotuberculosis OmpY and OmpF trimers were generated and the intra- and intermonomeric interactions stabilizing the porins were investigated. The difference in the thermal stability of OmpY and OmpF trimers was established to correlate with the difference in intermonomeric polar contacts.