4J4A

Crystal Structure of Engineered Trimeric Cortexillin-1 Coiled-Coil Variant

Summary for 4J4A

• Entry DOI: 10.2210/pdb4j4a/pdb
• Descriptor: Cortexillin-1, PHOSPHATE ION (3 entities in total)
• Functional Keywords: trimer, coiled-coil, de novo protein
• Biological source: Dictyostelium discoideum (Slime mold)
• Cellular location: Cytoplasm, cytoskeleton: Q54HG2
• Total number of polymer chains: 12
• Total formula weight: 37735.73

Authors

Bjelic, S.,Steinmetz, M.O.,Kammerer, R.A. (deposition date: 2013-02-06, release date: 2013-05-22, Last modification date: 2024-02-28)

Primary citation

Bjelic, S.,Wieser, M.,Frey, D.,Stirnimann, C.U.,Chance, M.R.,Jaussi, R.,Steinmetz, M.O.,Kammerer, R.A.
Structural basis for the oligomerization-state switch from a dimer to a trimer of an engineered cortexillin-1 coiled-coil variant.
Plos One, 8:e63370-e63370, 2013

PubMed Abstract: Coiled coils are well suited to drive subunit oligomerization and are widely used in applications ranging from basic research to medicine. The optimization of these applications requires a detailed understanding of the molecular determinants that control of coiled-coil formation. Although many of these determinants have been identified and characterized in great detail, a puzzling observation is that their presence does not necessarily correlate with the oligomerization state of a given coiled-coil structure. Thus, other determinants must play a key role. To address this issue, we recently investigated the unrelated coiled-coil domains from GCN4, ATF1 and cortexillin-1 as model systems. We found that well-known trimer-specific oligomerization-state determinants, such as the distribution of isoleucine residues at heptad-repeat core positions or the trimerization motif Arg-h-x-x-h-Glu (where h = hydrophobic amino acid; x = any amino acid), switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence, a site indispensable for coiled-coil formation. Because high-resolution structural information could not be obtained for the full-length, three-stranded cortexillin-1 coiled coil, we here report the detailed biophysical and structural characterization of a shorter variant spanning the trigger sequence using circular dichroism, anatytical ultracentrifugation and x-ray crystallography. We show that the peptide forms a stable α-helical trimer in solution. We further determined the crystal structure of an optimised variant at a resolution of 1.65 Å, revealing that the peptide folds into a parallel, three-stranded coiled coil. The two complemented R-IxxIE trimerization motifs and the additional hydrophobic core isoleucine residue adopt the conformations seen in other extensively characterized parallel, three-stranded coiled coils. These findings not only confirm the structural basis for the switch in oligomerization state from a dimer to a trimer observed for the full-length cortexillin-1 coiled-coil domain, but also provide further evidence for a general link between oligomerization-state specificity and trigger-sequence function.

PubMed: 23691037
DOI: 10.1371/journal.pone.0063370

Experimental method

X-RAY DIFFRACTION (1.6499 Å)