2b22 | pdb_00002b22
Antiparallel four-stranded coiled coil specified by a 3-3-1 hydrophobic heptad repeat
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| 2b22, resolution 2.00Å | |||||||||||||
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| Ligands: | NA | ||||||||||||
| Gene: | GCN4, AAS3, ARG9 (Saccharomyces cerevisiae) | ||||||||||||
| Related: | 2ZTA, 1GCM, 1GCL, 2B1F
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Overview
Coiled-coil sequences in proteins commonly share a seven-amino acid repeat with nonpolar side chains at the first (a) and fourth (d) positions. We investigate here the role of a 3-3-1 hydrophobic repeat containing nonpolar amino acids at the a, d, and g positions in determining the structures of coiled coils using mutants of the GCN4 leucine zipper dimerization domain. When three charged residues at the g positions in the parental sequence are replaced by nonpolar alanine or valine side chains, stable four-helix structures result. The X-ray crystal structures of the tetramers reveal antiparallel, four-stranded coiled coils in which the a, d, and g side chains interlock in a combination of knobs-into-knobs and knobs-into-holes packing. Interfacial interactions in a coiled coil can therefore be prescribed by hydrophobic-polar patterns beyond the canonical 3-4 heptad repeat. The results suggest that the conserved, charged residues at the g positions in the GCN4 leucine zipper can impart a negative design element to disfavor thermodynamically more stable, antiparallel tetramers.
About this Structure
2B22 is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Antiparallel four-stranded coiled coil specified by a 3-3-1 hydrophobic heptad repeat., Deng Y, Liu J, Zheng Q, Eliezer D, Kallenbach NR, Lu M, Structure. 2006 Feb;14(2):247-55. PMID:16472744
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