title: The strongly conserved carboxyl-terminus glycine-methionine motif of the Escherichia coli GroEL chaperonin is dispensable.
abstract: The universally distributed heat-shock proteins (HSPs) are divided into classes based on molecular weight and sequence conservation. The members of at least two of these classes, the HSP60s and the HSP70s, have chaperone activity. Most HSP60s and many HSP70s feature a striking motif at or near the carboxyl terminus which consists of a string of repeated glycine and methionine residues. We have altered the groEL gene (encoding the essential Escherichia coli HSP60 chaperonin) so that the protein produced lacks its 16 final (including nine gly, and five met) residues. This truncated product behaves like the intact protein in several in vitro tests, the only discernible difference between the two proteins being in the rate at which ATP is hydrolysed. GroELtr can substitute for GroEL in vivo although cells dependent for survival on the truncated protein survive slightly less well during the stationary phase of growth. Elevated levels of the wild-type protein can suppress a number of temperature-sensitive mutations; the truncated protein lacks this ability.
authors.affiliation: Institute of Cell and Molecular Biology, University of Edinburgh, UK.
authors.forename: N F
authors.initials: NF
authors.lastname: McLennan
authors.forename: A S
authors.initials: AS
authors.lastname: Girshovich
authors.forename: N M
authors.initials: NM
authors.lastname: Lissin
authors.forename: Y
authors.initials: Y
authors.lastname: Charters
authors.forename: M
authors.initials: M
authors.lastname: Masters
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D018834:Chaperonin 60; D004926:Escherichia coli / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010641:Phenotype; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D005656:Fungal Proteins; D006360:Heat-Shock Proteins