Repeating Amino Acids Point to Important Structural Motifs in NS3 and NS5 Proteins of Flaviviruses

Many studies point to conserved motifs in various proteins of the Orthoflavivirus genus. This study aimed to uniformly designate conserved motifs in two nonstructural proteins based on the "amino acid repeat" model and point out the connection, on the one hand, with their role in the functions of proteins and their role in the ecological strategy of the virus. Materials and Methods: It was supposed in the study, that some of the repeating amino acids in the protein sequence of the viruses remain conservative within a genus or a group and point to meaningful segments of the protein. The repeating amino acids were detected in all proteins of flavivirus, in the genomes of more than 70 virus types. The location of the repeats in the tertiary structure was analyzed. The position of conservative repeats in groups of viruses was associated, according to its vectors. Results: It was observed that NS3 and NS5 proteins have conservative repeats in different regions of the proteins. The genus-specific repeats QQ352-353 and KK461-462 of the interdomain region of the NS5 protein may be involved in blocking innate immunity through the STAT2 system. Also, group-specific repeats of a previously unexplored interface from the back side of EE438-439 helicase, RR450-451 and DDDD481-484, may be responsible for the difference in virus reproduction in ticks and mosquitoes. Conclusion: A method of amino acid repeats proves its effectiveness. Conservation of repeat within a genus may be important for virus survival. On the other hand, conservation of repeat within a group may have implications for viral propagation in a particular vector or host.