1xu6: Difference between revisions
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'''Structure of the C-terminal domain from Trypanosoma brucei Variant Surface Glycoprotein MITat1.2'''<br /> | '''Structure of the C-terminal domain from Trypanosoma brucei Variant Surface Glycoprotein MITat1.2'''<br /> | ||
==Overview== | ==Overview== | ||
The variant surface glycoprotein (VSG) of African trypanosomes has a | 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== | ==About this Structure== | ||
1XU6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Trypanosoma_brucei_brucei Trypanosoma brucei brucei]. Full crystallographic information is available from [http:// | 1XU6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Trypanosoma_brucei_brucei Trypanosoma brucei brucei]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XU6 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Carrington, M.]] | [[Category: Carrington, M.]] | ||
[[Category: Chattopadhyay, A.]] | [[Category: Chattopadhyay, A.]] | ||
[[Category: Jones, N | [[Category: Jones, N G.]] | ||
[[Category: Mott, H | [[Category: Mott, H R.]] | ||
[[Category: Nielsen, P | [[Category: Nielsen, P R.]] | ||
[[Category: Nietlispach, D.]] | [[Category: Nietlispach, D.]] | ||
[[Category: Voorheis, H | [[Category: Voorheis, H P.]] | ||
[[Category: cysteine knot]] | [[Category: cysteine knot]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:58:39 2008'' | ||
Revision as of 16:58, 21 February 2008
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Structure of the C-terminal domain from Trypanosoma brucei Variant Surface Glycoprotein MITat1.2
OverviewOverview
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 StructureAbout this Structure
1XU6 is a Single protein structure of sequence from Trypanosoma brucei brucei. Full crystallographic information is available from OCA.
ReferenceReference
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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