title: The N-terminal regions of beta and gamma subunits lower the solubility of adenosylcobalamin-dependent diol dehydratase.
abstract: Adenosylcobalamin-dependent diol dehydratase is one of essential components of carboxysome-like polyhedral bodies. It exists as a heterohexamer (alphabetagamma)(2), and its activity is recovered in a precipitant fraction of Klebsiella oxytoca and overexpressing Escherichia coli cells. Limited proteolysis of the enzyme with trypsin converted the enzyme into a highly soluble form without loss of enzyme activity. The N-terminal amino acid sequencing of the enzyme thus solubilized indicated that the N-terminal 20 and 16 amino acid residues had been removed from the beta and gamma subunits, respectively. Mutant enzymes with the same N-terminal truncations of either or both of the beta and gamma subunits were expressed on a high level in E. coli cells. All the mutant enzymes obtained were expressed in a soluble, active form. These results indicate that the N-terminal regions of the beta and gamma subunits lower the solubility of diol dehydratase. The mutant enzyme with the N-terminal truncations of both beta and gamma subunits was essentially indistinguishable in catalytic properties from recombinant wild-type enzyme or the enzyme purified from K. oxytoca in a soluble form.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Tobimatsu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kawata
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Toraya
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003038:Cobamides / Q000378:metabolism*; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D041121:Klebsiella oxytoca / Q000235:genetics; D008969:Molecular Sequence Data; D011408:Propanediol Dehydratase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012995:Solubility
chemical_list: D003038:Cobamides; D017931:DNA Primers; D011408:Propanediol Dehydratase; C000913:cobamamide