title: Self-assembly of the chaperonin GroEL nanocage induced at submicellar detergent.
abstract: Protein nanoassemblies possess unique advantage in biomedical applications such as drug delivery, biocatalysis and vaccine development. Despite recent accomplishment in atomic structure data, the underlying molecular mechanism of protein self-assembly remains elusive, where considerable heterogeneity is often involved. Here we use E. coli chaperonin GroEL, a tetradecameric protein with a molecular weight of 805 kDa, to probe its transformation from cage-like oligomers to protein nanofibers. We show that sodium dodecyl sulfate (SDS), a widely-used protein denaturant, at submicellar concentration binds to and causes partial distortion of GroEL apical domain. Subsequently, the GroEL apical domain with altered secondary structural content converts the GroEL oligomers into modular structural units which are observed to self-assemble into cylindrical nanofibers under an agitated incubation in a physiological buffer. Interestingly, through targeted mutagenesis where two cysteine residues are introduced at the entry site of GroEL cage, we found that the formation of GroEL nanoassembly could be modulated depending on the redox condition of incubation. Without the need of chemical engineering, tunable GroEL nanofibers built by controlled-assembly are among the largest nanoscale bioassembly with broad applications.
authors.affiliation: 1] Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan [2].
authors.forename: Jin
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1] Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan [2] [3].
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yagi
authors.affiliation: 1] Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan [2] Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Furutani
authors.affiliation: Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Asumi
authors.initials: A
authors.lastname: Inaguma
authors.affiliation: 1] Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan [2] Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Hao
authors.initials: H
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Goto
mesh_terms: D001665:Binding Sites; D018834:Chaperonin 60 / Q000737:chemistry* / Q000648:ultrastructure*; D003460:Crystallization / Q000379:methods; D008823:Micelles; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*
chemical_list: D018834:Chaperonin 60; D008823:Micelles; D046912:Multiprotein Complexes; D012967:Sodium Dodecyl Sulfate