1piq
CRYSTAL STRUCTURE OF GCN4-PIQ, A TRIMERIC COILED COIL WITH BURIED POLAR RESIDUES
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OverviewOverview
Coiled coils consist of two or more alpha-helices wrapped around each, other with a superhelical twist. The interfaces between helices of a, coiled coil are formed by hydrophobic amino acid residues packed in a, "knobs-into-holes" arrangement. Most naturally occurring coiled coils, however, also contain buried polar residues, as do the cores of the, majority of naturally occurring globular proteins. Two common buried polar, residues in both dimeric and trimeric coiled coils are asparagine and, glutamine. In dimeric coiled coils, buried asparagine, but not glutamine, residues have been shown to confer specificity of oligomerization. We have, placed a glutamine residue in the otherwise hydrophobic interior of a, stable trimeric coiled coil, GCN4-pII, to study the effect of this buried, polar residue in a trimeric coiled-coil environment. The resulting, peptide, GCN4-pIQI, is a discrete, trimeric coiled coil with a lower, stability than GCN4-pII. The crystal structure determined to 1.8 A shows, that GCN4-pIQI is a trimeric coiled coil with a chloride ion coordinated, by one buried glutamine residue from each monomer.
About this StructureAbout this Structure
1PIQ is a Single protein structure of sequence from [1] with CL and ACE as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of GCN4-pIQI, a trimeric coiled coil with buried polar residues., Eckert DM, Malashkevich VN, Kim PS, J Mol Biol. 1998 Dec 11;284(4):859-65. PMID:9837709
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