title: Cloning, characterization, and functional expression in Escherichia coli of chaperonin (groESL) genes from the phototrophic sulfur bacterium Chromatium vinosum.
abstract: A recombinant lambda phage which was able to propagate in groE mutants of Escherichia coli was isolated from a Chromatium vinosum genomic DNA library. A 4-kbp SalI DNA fragment, isolated from this phage and subcloned in plasmid vectors, carried the C. vinosum genes that allowed lambda growth in these mutants. Sequencing of this fragment indicated the presence of two open reading frames encoding polypeptides of 97 and 544 amino acids, respectively, which showed high similarity to the molecular chaperones GroES and GroEL, respectively, from several eubacteria and eukaryotic organelles. Expression of the cloned C. vinosum groESL genes in E. coli was greatly enhanced when the cells were transferred to growth temperatures that induce the heat shock response in this host. Coexpression in E. coli of C. vinosum groESL genes and the cloned ribulose bisphosphate carboxylase/oxygenase genes from different phototrophic bacteria resulted in an enhanced assembly of the latter enzymes. These results indicate that the cloned DNA fragment encodes C. vinosum chaperonins, which serve in the assembly process of oligomeric proteins. Phylogenic analysis indicates a close relationship between C. vinosum chaperonins and their homologs present in pathogenic species of the gamma subdivision of the eubacterial division Proteobacteria.
authors.affiliation: Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina.
authors.forename: R G
authors.initials: RG
authors.lastname: Ferreyra
authors.forename: F C
authors.initials: FC
authors.lastname: Soncini
authors.forename: A M
authors.initials: AM
authors.lastname: Viale
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D018833:Chaperonins / Q000235:genetics*; D002844:Chromatium / Q000235:genetics*; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006360:Heat-Shock Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; C097970:GroESL protein, Bacteria; D006360:Heat-Shock Proteins; D018833:Chaperonins