title: Stimulating the substrate folding activity of a single ring GroEL variant by modulating the cochaperonin GroES.
abstract: In mediating protein folding, chaperonin GroEL and cochaperonin GroES form an enclosed chamber for substrate proteins in an ATP-dependent manner. The essential role of the double ring assembly of GroEL is demonstrated by the functional deficiency of the single ring GroEL(SR). The GroEL(SR)-GroES is highly stable with minimal ATPase activity. To restore the ATP cycle and the turnover of the folding chamber, we sought to weaken the GroEL(SR)-GroES interaction systematically by concatenating seven copies of groES to generate groES(7). GroES Ile-25, Val-26, and Leu-27, residues on the GroEL-GroES interface, were substituted with Asp on different groES modules of groES(7). GroES(7) variants activate ATP activity of GroEL(SR), but only some restore the substrate folding function of GroEL(SR), indicating a direct role of GroES in facilitating substrate folding through its dynamics with GroEL. Active GroEL(SR)-GroES(7) systems may resemble mammalian mitochondrial chaperonin systems.
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405.
authors.forename: Melissa
authors.initials: M
authors.lastname: Illingworth
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ramsey
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405.
authors.forename: Zhida
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405. Electronic address: linchen@indiana.edu.
authors.forename: Lingling
authors.initials: L
authors.lastname: Chen
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D018835:Chaperonin 10 / Q000737:chemistry*; D018834:Chaperonin 60 / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D007532:Isoleucine / Q000737:chemistry; D007930:Leucine / Q000737:chemistry; D008291:Malate Dehydrogenase / Q000737:chemistry; D008928:Mitochondria / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry; D008968:Molecular Conformation; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011487:Protein Conformation; D017510:Protein Folding
chemical_list: D018835:Chaperonin 10; D018834:Chaperonin 60; D018832:Molecular Chaperones; D007532:Isoleucine; D001224:Aspartic Acid; D008291:Malate Dehydrogenase; D000251:Adenosine Triphosphatases; D007930:Leucine