Development of computer methods in molecular biology and fast growth of microbial genomics data enabled new approach based on selecting in silico antigenic components to design vaccine constructs. It is expected that application of this technology will eliminate side effects of new vaccines and reduce the time consumption and financial expenses. The bioinformatics methods of sequence analysis are used to reveal the most prospective proteins or protein fragments of infectious agents as candidates for vaccine design. In these studies the specialized molecular immunology databases are widely used. The new approach ("Reverse vaccinology") could help in designing vaccines against diseases where traditional methods are not successful, e.g. when the viral genome reveals the extreme variability and permanent changes of antigenic properties that make difficulties for selection of molecular targets for medicines and candidate vaccines. A number of informational resources are already designed to collect and provide genomic data on certain microbes or viruses. The peculiarity of such resources is presentation of data, characterizing the different genomic variants of the same infectious agents. These structural data coupled with information on functional/immune features and software tools have to compose basis for constructing a new generation of vaccines against "common" and new infections such as AIDS, Hepatitis C, and SARS. The approaches published in literature, as well as the authors' original results are discussed.

Sequences of the E1 and E2 envelope proteins of hepatitis C virus (HCV) (827 non-identical items) were collected from available sources and aligned. Analysis of the alignment identified regions with different sequence variability. It was found that 33% and 50% of positions within E1 and E2, respectively, were highly conservative. Such conservation can be considered as the minimum for maintaining stability of the three-dimensional structure and function of these proteins. Conserved cysteines in E1 and E2 (eight and 18 residues, respectively) were presumed to form intramolecular disulphide bonds. Both envelope proteins were predicted to contain 14 conservative glycosylation sites. Two additional glycosylation sites were predicted in 58% of E1 and 30% of E2 sequences within the corresponding regions. We describe the positions of six conservative regions in E1 and E2, which have several charged and aromatic residues known to participate frequently in protein-protein recognition. Peculiarities in the amino acid content of conservative fragments and putative differences in glycosylation were considered with regard to antigenic specificity and possible binding to surface structures of target cells. We also analysed the hypervariable region 1 (HVR1), located in the E2 protein. Aligned positions of HVR1 were described in relation to the maintenance of conformational stability and recognition of cell receptors.

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Heparan sulphate is one of the candidate receptors for hepatitis C virus (HCV). Envelope glycoproteins of HCV have been proposed to be responsible for recognition and binding with cell receptors. They are characterized by great genetic polymorphism. In this study the mapping of regions with glycosaminoglycan-binding properties within HCV envelope proteins has been undertaken. We prepared a set of overlapping peptides corresponding to conserved regions of these envelope proteins and analysed them by solid phase heparin-binding assay. The search for established glycosaminoglycan-binding motifs in the HCV envelope proteins showed the absence of the sites corresponding to the glycosaminoglycan-binding patterns in consensus sequence. We identified one highly conserved and two less conserved heparin-binding sequences within the envelope protein E2 based on solid phase assay results. We did not find any differences in binding efficiency of these peptides with heparin, heparan sulphate or dextran sulphate. Our data supported the specific association between HCV envelope protein E2 and cell surface glycosaminoglycans. We hypothesize that identified regions from E2 can contribute to HCV binding to cell surface glycosaminoglycans.