1xu6
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(New page: 200px<br /><applet load="1xu6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xu6" /> '''Structure of the C-terminal domain from Tryp...)
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Revision as of 04:13, 21 November 2007
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Structure of the C-terminal domain from Trypanosoma brucei Variant Surface Glycoprotein MITat1.2
Overview
The variant surface glycoprotein (VSG) of African trypanosomes has a, structural role in protecting other cell surface proteins from effector, molecules of the mammalian immune system and also undergoes antigenic, variation necessary for a persistent infection in a host. Here we have, reported the solution structure of a VSG type 2 C-terminal domain from, MITat1.2, completing the first structure of both domains of a VSG. The, isolated C-terminal domain is a monomer in solution and forms a novel, fold, which commences with a short alpha-helix followed by a single turn, of 3(10)-helix and connected by a short loop to a small anti-parallel, beta-sheet and then a longer alpha-helix at the C terminus. This compact, domain is flanked by two unstructured regions. The structured part of the, domain contains 42 residues, and the core comprises 2 disulfide bonds and, 2 hydrophobic residues. These cysteines and hydrophobic residues are, conserved in other VSGs, and we have modeled the structures of two further, VSG C-terminal domains using the structure of MITat1.2. The models suggest, that the overall structure of the core is conserved in the different VSGs, but that the C-terminal alpha-helix is of variable length and depends on, the presence of charged residues. The results provided evidence for a, conserved tertiary structure for all the type 2 VSG C-terminal domains, indicated that VSG dimers form through interactions between N-terminal, domains, and showed that the selection pressure for sequence variation, within a conserved tertiary structure acts on the whole of the VSG, molecule.
About this Structure
1XU6 is a Single protein structure of sequence from Trypanosoma brucei brucei. Full crystallographic information is available from OCA.
Reference
Structure of the C-terminal domain from Trypanosoma brucei variant surface glycoprotein MITat1.2., Chattopadhyay A, Jones NG, Nietlispach D, Nielsen PR, Voorheis HP, Mott HR, Carrington M, J Biol Chem. 2005 Feb 25;280(8):7228-35. Epub 2004 Nov 22. PMID:15557330
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