title: Seeing GroEL at 6 A resolution by single particle electron cryomicroscopy.
abstract: We present a reconstruction of native GroEL by electron cryomicroscopy (cryo-EM) and single particle analysis at 6 A resolution. alpha helices are clearly visible and beta sheet density is also visible at this resolution. While the overall conformation of this structure is quite consistent with the published X-ray data, a measurable shift in the positions of three alpha helices in the intermediate domain is observed, not consistent with any of the 7 monomeric structures in the Protein Data Bank model (1OEL). In addition, there is evidence for slight rearrangement or flexibility in parts of the apical domain. The 6 A resolution cryo-EM GroEL structure clearly demonstrates the veracity and expanding scope of cryo-EM and the single particle reconstruction technique for macromolecular machines.
authors.affiliation: National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Ludtke
authors.forename: Dong-Hua
authors.initials: DH
authors.lastname: Chen
authors.forename: Jiu-Li
authors.initials: JL
authors.lastname: Song
authors.forename: David T
authors.initials: DT
authors.lastname: Chuang
authors.forename: Wah
authors.initials: W
authors.lastname: Chiu
mesh_terms: D018834:Chaperonin 60 / Q000737:chemistry*; D020285:Cryoelectron Microscopy / Q000379:methods*; D018360:Crystallography, X-Ray; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary
chemical_list: D018834:Chaperonin 60