title: Helical crystallization on lipid nanotubes: streptavidin as a model protein.
abstract: In this study, we use streptavidin (SA) as a model system to study helical protein array formation on lipid nanotubes, an alternative to 2D studies on lipid monolayers. We demonstrate that wild-type and a mutant form of SA form helical arrays on biotinylated lipid nanotubes. 3D maps from helical arrays of wild-type and mutant SA were reconstructed using two different approaches: Fourier-Bessel methods and an iterative single particle algorithm. The maps show that wild-type and mutant streptavidin molecules order differently. The molecular packing arrangements of SA on the surface of the lipid nanotubes differ from previously reported lattice packing of SA on biotinylated monolayers. Helical crystallization on lipid nanotubes presents an alternative platform to explore fundamentals of protein ordering, intermolecular protein interaction and phase behavior. We demonstrate that lipid nanotubes offer a robust and reproducible substrate for forming helical protein arrays which present a means for studying protein structure and structure-function relationships.
authors.affiliation: The Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Thanh X
authors.initials: TX
authors.lastname: Dang
authors.forename: Sammy J
authors.initials: SJ
authors.lastname: Farah
authors.forename: Alice
authors.initials: A
authors.lastname: Gast
authors.forename: Channing
authors.initials: C
authors.lastname: Robertson
authors.forename: Bridget
authors.initials: B
authors.lastname: Carragher
authors.forename: Edward
authors.initials: E
authors.lastname: Egelman
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Wilson-Kubalek
mesh_terms: D003460:Crystallization / Q000379:methods; D008055:Lipids / Q000737:chemistry*; D009154:Mutation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry*; D040081:Protein Array Analysis / Q000379:methods*; D019809:Streptavidin / Q000737:chemistry* / Q000235:genetics
chemical_list: D008055:Lipids; D019809:Streptavidin