title: Gene analysis, expression, and characterization of an intracellular α-amylase from the extremely halophilic archaeon Haloarcula japonica.
abstract: Haloarcula japonica is an extremely halophilic archaeon that requires high concentrations of NaCl to grow. Recently the draft genome sequence of Ha. japonica was determined, and a gene encoding an α-amylase, malA, was identified. The deduced amino acid sequence of MalA, consisting of 663 amino acids, showed homology to α-amylase family enzymes. The sequence did not contain a secretion signal sequence, indicating that the protein is a cytoplasmic enzyme. Transcription of the malA gene was confirmed by reverse transcription (RT)-PCR, and the transcription start site was determined by a 5'-RACE experiment. The malA gene was cloned and expressed in Ha. japonica. The recombinant MalA was purified and characterized. MalA required a high concentration of NaCl for starch-hydrolyzing activity. It showed higher activity on soluble starch, amylose, and amylopectin, and lower activity on glycogen.
authors: Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan.
authors: Masahiko
authors: M
authors: Onodera
authors: Rie
authors: R
authors: Yatsunami
authors: Wataru
authors: W
authors: Tsukimura
authors: Toshiaki
authors: T
authors: Fukui
authors: Kaoru
authors: K
authors: Nakasone
authors: Tomonori
authors: T
authors: Takashina
authors: Satoshi
authors: S
authors: Nakamura
mesh_terms: D000595:Amino Acid Sequence; D000687:Amylopectin / Q000378:metabolism; D000688:Amylose / Q000378:metabolism; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology; D015870:Gene Expression / Q000187:drug effects; D019613:Haloarcula / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D054712:Salinity; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D013213:Starch / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D000516:alpha-Amylases / Q000235:genetics / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D011994:Recombinant Proteins; D012965:Sodium Chloride; D013213:Starch; D000688:Amylose; D000687:Amylopectin; D000516:alpha-Amylases