1T8Z

Atomic structure of a tryptophan-zipper pentamer.

(2004) Proc Natl Acad Sci U S A 101: 16156-16161

• PubMed: 15520380 Search on PubMedSearch on PubMed Central
• 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.

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Organizational Affiliation: 

Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA.