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Title: A Seven-Helix Coiled Coil

Abstract

Coiled-coil proteins contain a characteristic seven-residue sequence repeat whose positions are designated a to g. The interacting surface between {alpha}-helices in a classical coiled coil is formed by interspersing nonpolar side chains at the a and d positions with hydrophilic residues at the flanking e and g positions. To explore how the chemical nature of these core amino acids dictates the overall coiled-coil architecture, we replaced all eight e and g residues in the GCN4 leucine zipper with nonpolar alanine side chains. Surprisingly, the alanine-containing mutant forms a stable {alpha}-helical heptamer in aqueous solution. The 1.25-{angstrom} resolution crystal structure of the heptamer reveals a parallel seven-stranded coiled coil enclosing a large tubular channel with an unusual heptad register shift between adjacent staggered helices. The overall geometry comprises two interleaved hydrophobic helical screws of interacting cross-sectional a and d layers that have not been seen before. Moreover, asparagines at the a positions play an essential role in heptamer formation by participating in a set of buried interhelix hydrogen bonds. These results demonstrate that heptad repeats containing four hydrophobic positions can direct assembly of complex, higher-order coiled-coil structures with rich diversity for close packing of {alpha}-helices.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930246
Report Number(s):
BNL-80934-2008-JA
TRN: US200822%%1418
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proceedings of the National Academy of Sciences of the USA; Journal Volume: 103; Journal Issue: 42
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 36 MATERIALS SCIENCE; ALANINES; AMINO ACIDS; AQUEOUS SOLUTIONS; ARCHITECTURE; CRYSTAL STRUCTURE; FASTENERS; GEOMETRY; HYDROGEN; LAYERS; LEUCINE; MUTANTS; PROTEINS; RESIDUES; RESOLUTION; STOWING; SURFACES; national synchrotron light source

Citation Formats

Liu,J., Zheng, Q., Deng, Y., Cheng, C., Kallenbach, N., and Lu, M. A Seven-Helix Coiled Coil. United States: N. p., 2006. Web. doi:10.1073/pnas.0604871103.
Liu,J., Zheng, Q., Deng, Y., Cheng, C., Kallenbach, N., & Lu, M. A Seven-Helix Coiled Coil. United States. doi:10.1073/pnas.0604871103.
Liu,J., Zheng, Q., Deng, Y., Cheng, C., Kallenbach, N., and Lu, M. Sun . "A Seven-Helix Coiled Coil". United States. doi:10.1073/pnas.0604871103.
@article{osti_930246,
title = {A Seven-Helix Coiled Coil},
author = {Liu,J. and Zheng, Q. and Deng, Y. and Cheng, C. and Kallenbach, N. and Lu, M.},
abstractNote = {Coiled-coil proteins contain a characteristic seven-residue sequence repeat whose positions are designated a to g. The interacting surface between {alpha}-helices in a classical coiled coil is formed by interspersing nonpolar side chains at the a and d positions with hydrophilic residues at the flanking e and g positions. To explore how the chemical nature of these core amino acids dictates the overall coiled-coil architecture, we replaced all eight e and g residues in the GCN4 leucine zipper with nonpolar alanine side chains. Surprisingly, the alanine-containing mutant forms a stable {alpha}-helical heptamer in aqueous solution. The 1.25-{angstrom} resolution crystal structure of the heptamer reveals a parallel seven-stranded coiled coil enclosing a large tubular channel with an unusual heptad register shift between adjacent staggered helices. The overall geometry comprises two interleaved hydrophobic helical screws of interacting cross-sectional a and d layers that have not been seen before. Moreover, asparagines at the a positions play an essential role in heptamer formation by participating in a set of buried interhelix hydrogen bonds. These results demonstrate that heptad repeats containing four hydrophobic positions can direct assembly of complex, higher-order coiled-coil structures with rich diversity for close packing of {alpha}-helices.},
doi = {10.1073/pnas.0604871103},
journal = {Proceedings of the National Academy of Sciences of the USA},
number = 42,
volume = 103,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}