StudioG24SecL04Tpc5: Difference between revisions
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==VlsE== | ==VlsE== | ||
The causative agent of [http://en.wikipedia.org/wiki/Lyme_disease Lyme Disease], a multi-stage infection, is a family of spirochetes found in the guts of Ixodes ticks. The Variable Major Protein (VMP)-like sequence Expressed (VlsE) is the specific outer-surface lipoprotein that enables the spirochete to evade immune response through mechanisms of [http://en.wikipedia.org/wiki/Antigenic_variation antigenic variation]. In addition to inducing a strong immune response in the host, VlsE is useful in the serodiagnosis of Lyme disease.<ref>PMID: 11923306</ref> | The causative agent of [http://en.wikipedia.org/wiki/Lyme_disease Lyme Disease], a multi-stage infection, is a family of spirochetes found in the guts of Ixodes ticks. The Variable Major Protein (VMP)-like sequence Expressed (VlsE) is the specific outer-surface lipoprotein that enables the spirochete to evade immune response through mechanisms of [http://en.wikipedia.org/wiki/Antigenic_variation antigenic variation]. In addition to inducing a strong immune response in the host, VlsE is useful in the serodiagnosis of Lyme disease.<ref>PMID: 11923306</ref> | ||
==Structural Overview== | ==Structural Overview== | ||
The relationship between VlsE structure and its possible functions were determined by the three dimensional structure of VlsE from the [http://en.wikipedia.org/wiki/Borrelia_burgdorferi ''Borrelia burgdorferi''] <br> 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. | The relationship between VlsE structure and its possible functions were determined by the three dimensional structure of VlsE from the [http://en.wikipedia.org/wiki/Borrelia_burgdorferi ''Borrelia burgdorferi''] <br> 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. | ||
===Direct Repeat=== | |||
The ''vlsE'' region containing the invariable and variable regions are bound by the 17 base pair direct repeats (DR). DR1, demarcating the beginning of the cassette region is part of helix alpha-3 at the membrane proximal end of VlsE1 and is exposed on the surface of the protein. DR2 is found at the end of the cassette region and is surface exposed. However, DR2 is located at the membrane distal surface and a slight portion of the lateral VlsE1 surface. <ref>PMID: 11923306</ref> | |||
