title: Directed evolution of substrate-optimized GroEL/S chaperonins.
abstract: GroEL/S chaperonin ring complexes fold many unrelated proteins. To understand the basis and extent of the chaperonin substrate spectrum, we used rounds of selection and DNA shuffling to obtain GroEL/S variants that dramatically enhanced folding of a single substrate-green fluorescent protein (GFP). Changes in the substrate-optimized chaperonins increase the polarity of the folding cavity and alter the ATPase cycle. These findings reveal a surprising plasticity of GroEL/S, which can be exploited to aid folding of recombinant proteins. Our studies also reveal a conflict between specialization and generalization of chaperonins as increased GFP folding comes at the expense of the ability of GroEL/S to fold its natural substrates. This conflict and the nature of the ring structure may help explain the evolution of cellular chaperone systems.
authors.affiliation: Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco 94143, USA.
authors.forename: Jue D
authors.initials: JD
authors.lastname: Wang
authors.forename: Christophe
authors.initials: C
authors.lastname: Herman
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Tipton
authors.forename: Carol A
authors.initials: CA
authors.lastname: Gross
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Weissman
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D018835:Chaperonin 10 / Q000235:genetics / Q000378:metabolism*; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism*; D019020:Directed Molecular Evolution; D004926:Escherichia coli; D005057:Eukaryotic Cells / Q000378:metabolism*; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011387:Prokaryotic Cells / Q000378:metabolism*; D017510:Protein Folding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism
chemical_list: D018835:Chaperonin 10; D018834:Chaperonin 60; D008164:Luminescent Proteins; D020033:Protein Isoforms; D049452:Green Fluorescent Proteins; D000251:Adenosine Triphosphatases