2r2v: Difference between revisions
New page: '''Unreleased structure''' The entry 2r2v is ON HOLD until Paper Publication Authors: Liu, J., Lu, M. Description: Sequence Determinants of the Topology of the Lac Repressor Tetrameric... |
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{{STRUCTURE_2r2v| PDB=2r2v | SCENE= }} | |||
'''Sequence Determinants of the Topology of the Lac Repressor Tetrameric Coiled Coil''' | |||
==Overview== | |||
Predictive understanding of how the folded, functional shape of a native protein is encoded in the linear sequence of its amino acid residues remains an unsolved challenge in modern structural biology. Antiparallel four-stranded coiled coils are relatively simple protein structures that embody a heptad sequence repeat and rich diversity for tertiary packing of alpha-helices. To explore specific sequence determinants of the lac repressor coiled-coil tetramerization domain, we have engineered a set of buried nonpolar side chains at the a-, d-, and e-positions into the hydrophobic interior of the dimeric GCN4 leucine zipper. Circular dichroism and equilibrium ultracentrifugation studies show that this core variant (GCN4-pAeLV) forms a stable tetrameric structure with a reversible and highly cooperative thermal unfolding transition. The X-ray crystal structure at 1.9 A reveals that GCN4-pAeLV is an antiparallel four-stranded coiled coil of the lac repressor type in which the a, d, and e side chains associate by means of combined knobs-against-knobs and knobs-into-holes packing with a characteristic interhelical offset of 0.25 heptad. Comparison of the side chain shape and packing in the antiparallel tetramers shows that the burial of alanine residues at the e positions between the neighboring helices of GCN4-pAeLV dictates both the antiparallel orientation and helix offset. This study fills in a gap in our knowledge of the determinants of structural specificity in antiparallel coiled coils and improves our understanding of how specific side chain packing forms the teritiary structure of a functional protein. | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun | ==About this Structure== | ||
2R2V is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2R2V OCA]. | |||
==Reference== | |||
Conformational specificity of the lac repressor coiled-coil tetramerization domain., Liu J, Zheng Q, Deng Y, Li Q, Kallenbach NR, Lu M, Biochemistry. 2007 Dec 25;46(51):14951-9. Epub 2007 Dec 4. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18052214 18052214] | |||
[[Category: Saccharomyces cerevisiae]] | |||
[[Category: Single protein]] | |||
[[Category: Liu, J.]] | |||
[[Category: Lu, M.]] | |||
[[Category: Anti-parallel tetramer]] | |||
[[Category: Coiled coil]] | |||
[[Category: De novo protein]] | |||
[[Category: Protein design]] | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 18 12:04:08 2008'' | |||