StudioG24SecL04Tpc5: Difference between revisions
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==Structural Overview== | ==Structural Overview== | ||
The relationship between VlsE structure and its possible functions were determined by the three dimensional structure of VlsE from the'' | The relationship between VlsE structure and its possible functions were determined by the three dimensional structure of VlsE from the'' Borrelia burgdorferi''[http://en.wikipedia.org/wiki/Borrelia_burgdorferi] B31 strain. <ref>PMID: 11923306</ref> VlsE is shown to be composed of four sub-units, each consisting of a variable domain flanked by two invariable domains (Liang). The variable domains themselves contain six <scene name='StudioG24SecL04Tpc5/Variable_region/2'>variable regions</scene> (VR) interspersed amongst six invariable regions (IR). The IRs are embedded deep within the protein covered by alpha helical loops. The IRs are embedded deep within the protein being essentially shielded by the VRs which represent 37% of the total surface area while containing less than 26% of the primary protein sequence. <ref>PMID: 11923306</ref> The six VRs entirely cover the distal portion of the protein with about 50% of their theoretical surface area exposed to the surface for immune response. <ref>PMID: 11923306</ref>. In contrast, the portion of the sub-unit responsible for the antigenic variation in the VlsE as well as inducing the host’s immune response only exposes about 13.7% of its surface. Being shielded by the IRs, the host’s antibodies are restricted to interact with a very limited number of residues rendering any antigenic response futile. | ||
===Variable Region=== | ===Variable Region=== | ||
The outer surface lipoprotein of ''Borrelia burgdorferi'' | The outer surface lipoprotein of ''Borrelia burgdorferi'' uses antigenic variation via gene conversion to evade host immune response. Crystal structure of VlsE1, a recombinant variant protein of VlsE, reveals six <scene name='StudioG24SecL04Tpc5/Variable_region/2'>variable regions</scene> that form loop structures that entirely cover the membrane distal end of the protein. <ref>PMID: 11923306</ref> Almost 50% of the variable region’s surface area is exposed on the surface of | ||
<scene name='StudioG24SecL04Tpc5/Vlse_cassete_region_highlight/1'>VlsE</scene>. There are three major areas of the membrane distal portion on the protein surface that undergo antigenic variation [http://en.wikipedia.org/wiki/Antigenic_variation]. <ref>PMID: 11923306</ref> It is likely that amino acid mutations of these residues change conformation of the looped structures and therefore vary the epitope [http://en.wikipedia.org/wiki/Epitope] throughout each variable region. Immune systems are overwhelmed with an astronomical number of different antigens. The loop structures cover predominantly the α-helical invariant regions of the protein. <ref>PMID: 11923306</ref>It is speculated that the locations of these variable regions on the membrane distal end shield the conserved regions of VlsE from antibody interaction and thereby contribute to immune evasion. <ref>PMID: 11923306</ref> | <scene name='StudioG24SecL04Tpc5/Vlse_cassete_region_highlight/1'>VlsE</scene>. There are three major areas of the membrane distal portion on the protein surface that undergo antigenic variation [http://en.wikipedia.org/wiki/Antigenic_variation]. <ref>PMID: 11923306</ref> It is likely that amino acid mutations of these residues change conformation of the looped structures and therefore vary the epitope [http://en.wikipedia.org/wiki/Epitope] throughout each variable region. Immune systems are overwhelmed with an astronomical number of different antigens. The loop structures cover predominantly the α-helical invariant regions of the protein. <ref>PMID: 11923306</ref>It is speculated that the locations of these variable regions on the membrane distal end shield the conserved regions of VlsE from antibody interaction and thereby contribute to immune evasion. <ref>PMID: 11923306</ref> | ||
