Structural highlights
Function[VSM1_TRYBB] VSG forms a coat on the surface of the parasite. The trypanosome evades the immune response of the host by expressing a series of antigenically distinct VSGs from an estimated 1000 VSG genes. Publication Abstract from PubMedThe most prominent defence of the unicellular parasite Trypanosoma brucei against the host immune system is a dense coat that comprises a variant surface glycoprotein (VSG). Despite the importance of the VSG family, no complete structure of a VSG has been reported. Making use of high-resolution structures of individual VSG domains, we employed small-angle X-ray scattering to elucidate the first two complete VSG structures. The resulting models imply that the linker regions confer great flexibility between domains, which suggests that VSGs can adopt two main conformations to respond to obstacles and changes of protein density, while maintaining a protective barrier at all times. Single-molecule diffusion measurements of VSG in supported lipid bilayers substantiate this possibility, as two freely diffusing populations could be detected. This translates into a highly flexible overall topology of the surface VSG coat, which displays both lateral movement in the plane of the membrane and variation in the overall thickness of the coat.The structures of a variant surface glycoprotein (VSG) from Trypanosoma brucei suggest that VSGs adopt different conformations to respond to obstacles present in the cell membrane, enabling them to maintain a protective coat at all times. Structural basis for the shielding function of the dynamic trypanosome variant surface glycoprotein coat.,Bartossek T, Jones NG, Schafer C, Cvitkovic M, Glogger M, Mott HR, Kuper J, Brennich M, Carrington M, Smith AS, Fenz S, Kisker C, Engstler M Nat Microbiol. 2017 Sep 11. doi: 10.1038/s41564-017-0013-6. PMID:28894098[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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