A seven-helix coiled coil

@article{citeulike:904353, 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-A 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. 10.1073/pnas.0604871103}, author = {Liu, Jie and Zheng, Qi and Deng, Yiqun and Cheng, Chao-Sheng and Kallenbach, Neville R. and Lu, Min }, citeulike-article-id = {904353}, journal = {PNAS}, keywords = {buried\_polar\_interactions, cavity, helixhelix\_interfaces, protein\_design, protein\_structure}, month = {October}, number = {42}, pages = {15457--15462}, posted-at = {2006-10-19 00:24:29}, priority = {0}, title = {A seven-helix coiled coil}, url = {http://www.pnas.org/cgi/content/abstract/103/42/15457}, volume = {103}, year = {2006} }

TY - JOUR ID - citeulike:904353 L3 - citeulike-article-id:904353 TI - A seven-helix coiled coil JF - PNAS VL - 103 IS - 42 SP - 15457 EP - 15462 N2 - 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-A 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. 10.1073/pnas.0604871103 KW - buried_polar_interactions KW - cavity KW - helixhelix_interfaces KW - protein_design KW - protein_structure AU - Liu, Jie AU - Zheng, Qi AU - Deng, Yiqun AU - Cheng, Chao-Sheng AU - Kallenbach, Neville AU - Lu, Min PY - 2006/10/17/ UR - http://www.pnas.org/cgi/content/abstract/103/42/15457 ER -