Download MendeleyAtomic structure of a tryptophan-zipper pentamer.
Liu, J., Yong, W., Deng, Y., Kallenbach, N.R., Lu, M.(2004) Proc Natl Acad Sci U S A 101: 16156-16161
- PubMed: 15520380
- DOI: https://doi.org/10.1073/pnas.0405319101
- Primary Citation of Related Structures:
1T8Z - PubMed Abstract:
Coiled-coil motifs are ubiquitous mediators of specific protein-protein interactions through the formation of interlocking hydrophobic seams between alpha-helical chains. Residues that form these seams occur at the first (a) and fourth (d) positions of a characteristic 7-aa repeat and are primarily aliphatic. The potential of aromatic residues to promote helix association in a coiled coil was explored by engineering a "Trp-zipper" protein with Trp residues at all 14 a and d positions. The protein forms a discrete, stable, alpha-helical pentamer in water at physiological pH. Its 1.45-A crystal structure reveals a parallel, five-stranded coiled coil, a previously uncharacterized type of "knobs-into-holes" packing interaction between interfacial Trp side chains, and an unusual approximately 8-A-diameter axial channel lined with indole rings that is filled with polyethylene glycol 400 and water and sulfate ion molecules. The engineered Trp-zipper pentamer enlarges current views of coiled-coil assembly, molecular recognition, and protein engineering, and may serve as a soluble model for membrane ion channels.
Organizational Affiliation:
Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA.
