2b22

From Proteopedia

Antiparallel four-stranded coiled coil specified by a 3-3-1 hydrophobic heptad repeat

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 with NA as ligand. 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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