title: Novel trimeric adenylate kinase from an extremely thermoacidophilic archaeon, Sulfolobus solfataricus: molecular cloning, nucleotide sequencing, expression in Escherichia coli, and characterization of the recombinant enzyme.
abstract: A gene coding for adenylate kinase was cloned from an extremely thermoacidophilic archaeon Sulfolobus solfataricus. The open reading frame of the sequenced gene consisted of 585 nucleotides coding for a polypeptide of 195 amino acid residues with a calculated molecular weight of 21,325. Although the S. solfataricus adenylate kinase, which belonged to the small variants of the adenylate kinase family, had low sequence identities with bacterial and eukaryotic enzymes, a functionally important glycine-rich region and also two invariant arginine residues were conserved in the sequence of the S. solfataricus enzyme. The recombinant enzyme, overexpressed in Escherichia coli and purified to homogeneity, had high affinity for AMP and high thermal stability, comparable to the extremely thermostable enzyme from a similar archaeon, S. acidocaldarius. Furthermore, gel filtration and sedimentation analyses showed that the S. solfataricus adenylate kinase was a homotrimer in solution, which is a novel subunit structure for nucleoside monophosphate kinases.
authors.affiliation: Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan. tokajima@sanken.osaka-u.ac.jp
authors.forename: Toshihide
authors.initials: T
authors.lastname: Okajima
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kitaguchi
authors.forename: Kumiko
authors.initials: K
authors.lastname: Fujii
authors.forename: Hidetada
authors.initials: H
authors.lastname: Matsuoka
authors.forename: Sachio
authors.initials: S
authors.lastname: Goto
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Tanizawa
mesh_terms: D000263:Adenylate Kinase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D015723:Gene Library; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016944:Sulfolobus / Q000201:enzymology*
chemical_list: D011994:Recombinant Proteins; D000263:Adenylate Kinase; D004259:DNA-Directed DNA Polymerase