[Development of approaches to studying the structural and functional organization of protein molecules aboard the International space station].
To solve the problems of biological safety of the cosmonaut on long-duration space mission and prediction of changes in macroorganism as a whole and constituting protein molecules under these conditions, it is important to study the influence of spaceflight factors (SFF) on microorganisms-carriers of modeled structures, protein molecules and pro- and eukaryotic genes in particular. Within the framework of scientific cooperation NAUKA-NASA, the authors proposed a model system of prokaryotic producers of pro- and eukaryotic proteins--staphylococcus alpha-toxin (SAT)--as a key protein in pathogenesis of staphylococcal infections, and human leukocytic interferon (HuIFN-alpha) as one of the homeostasis regulating proteins with well-studied structural and functional properties. Recombinant strains of E. coli with either a single or duplicated HuIFN-alpha 2b gene or other genes of the HuIFN-alpha family: HuIFN-alpha 8a, HuIFN-alpha 10a and HuIFN-alpha 14a were selected as producers of SAT and HuIFN-alpha. This biotechnologic system allows imitation and assessment of the SFF mutagenic effect both at the levels of genome of strain-carrier and gene-insertion and expressed CAT and HuIFN-alpha molecules including transcription, translation, assembly and post-translatory modifications of the target-protein. The developed methodology allows determination of highly mutable and conservative regions in the primary structure of a hypothetical protein associated with its functional activity, prediction of specific amino acid substitutes in these regions, and comparison of test calculations with a pool of natural mutations in the family of proteins under study. The structural/functional analysis of proteins and HuIFN-alpha genes made it possible to isolate and systematize functionally significant areas in the structure of hypothetical protein HuUFN-alpha, on the basis of which the most probable amino acid substitutions were prognosticated. This will present a possibility to identify expectable mutation events in HuIFN-alpha proteins, which so far have not been found in natural genes of the human interferon. Comparison of results of SFF modeling and space experiments aboard the International Space Station with monitoring of HuIFN-alpha mutant forms will help estimation of the extent of influence of the spaceflight factors on evolution of protein molecules.