Atomic structure of a tryptophan-zipper pentamer

作者：Liu J; Yong W; Deng YQ; Kallenbach NR; Lu M^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2004, 101(46): 16156-16161.

DOI：10.1073/pnas.0405319101

• coiled coils
• protein design
• protein structure

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-Angstrom 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 approximate to8-Angstrom-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.

• 出版日期2004-11-16