1gjz
From Proteopedia
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| - | + | {{STRUCTURE_1gjz| PDB=1gjz | SCENE= }} | |
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'''SOLUTION STRUCTURE OF A DIMERIC N-TERMINAL FRAGMENT OF HUMAN UBIQUITIN''' | '''SOLUTION STRUCTURE OF A DIMERIC N-TERMINAL FRAGMENT OF HUMAN UBIQUITIN''' | ||
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[[Category: Evans, P A.]] | [[Category: Evans, P A.]] | ||
[[Category: Stott, K.]] | [[Category: Stott, K.]] | ||
| - | [[Category: | + | [[Category: Dimer]] |
| - | [[Category: | + | [[Category: Protein dissection]] |
| - | [[Category: | + | [[Category: Ubiquitin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:40:17 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:40, 2 May 2008
SOLUTION STRUCTURE OF A DIMERIC N-TERMINAL FRAGMENT OF HUMAN UBIQUITIN
Overview
Previous peptide dissection and kinetic experiments have indicated that in vitro folding of ubiquitin may proceed via transient species in which native-like structure has been acquired in the first 45 residues. A peptide fragment, UQ(1-51), encompassing residues 1 to 51 of ubiquitin was produced in order to test whether this portion has propensity for independent self-assembly. Surprisingly, the construct formed a folded symmetrical dimer that was stabilised by 0.8 M sodium sulphate at 298 K (the S state). The solution structure of the UQ(1-51) dimer was determined by multinuclear NMR spectroscopy. Each subunit of UQ(1-51) consists of an N-terminal beta-hairpin followed by an alpha-helix and a final beta-strand, with orientations similar to intact ubiquitin. The dimer is formed by the third beta-strand of one subunit interleaving between the hairpin and third strand of the other to give a six-stranded beta-sheet, with the two alpha-helices sitting on top. The helix-helix and strand portions of the dimer interface also mimic related features in the structure of ubiquitin. The structural specificity of the UQ(1-51) peptide is tuneable: as the concentration of sodium sulphate is decreased, near-native alternative conformations are populated in slow chemical exchange. Magnetization transfer experiments were performed to characterize the various species present in 0.35 M sodium sulphate, namely the S state and two minor forms. Chemical shift differences suggest that one minor form is very similar to the S state, while the other experiences a significant conformational change in the third strand. A segmental rearrangement of the third strand in one subunit of the S state would render the dimer asymmetric, accounting for most of our results. Similar small-scale transitions in proteins are often invoked to explain solvent exchange at backbone amide proton sites that have an intermediate level of protection.
About this Structure
1GJZ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure and properties of a dimeric N-terminal fragment of human ubiquitin., Bolton D, Evans PA, Stott K, Broadhurst RW, J Mol Biol. 2001 Dec 7;314(4):773-87. PMID:11733996 Page seeded by OCA on Fri May 2 17:40:17 2008
