title: Difference in NaCl tolerance of membrane-bound 5'-nucleotidases purified from deep-sea and brackish water Shewanella species.
abstract: Shewanella species are widely distributed in sea, brackish, and fresh water areas, growing psychrophilically or mesophilically, and piezophilically or piezo-sensitively. Here, membrane-bound 5'-nucleotidases (NTases) from deep-sea Shewanella violacea and brackish water Shewanella amazonensis were examined from the aspect of NaCl tolerance to gain an insight into protein stability against salt. Both NTases were single polypeptides with molecular masses of ~59 kDa, as determined on mass spectroscopy. They similarly required 10 mM MgCl2for their activities, and they exhibited the same pH dependency and substrate specificity for 5'-nucleotides. However, S. violacea 5'-nucleotidase (SVNTase) was active enough in the presence of 2.5 M NaCl, whereas S. amazonensis 5'-nucleotidase (SANTase) exhibited significantly reduced activity with the same concentration of the salt. Although SVNTase and SANTase exhibited high sequence identity (69.7%), differences in the ratio of acidic to basic amino acid residues and the number of potential salt bridges maybe being responsible for the difference in the protein stability against salt. 5'-Nucleotidases from these Shewanella species will provide useful information regarding NaCl tolerance, which may be fundamental for understanding bacterial adaptation to growth environments.
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8528, Japan.
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Kuribayashi
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8528, Japan.
authors.forename: Sotaro
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8528, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Masanari
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Yamanaka
authors.affiliation: Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai, Kobe, Hyogo, 657-8501, Japan. wakaists@pegasus.kobe-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakai
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8528, Japan. sambongi@hiroshima-u.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sambongi
mesh_terms: D015720:5'-Nucleotidase / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D002462:Cell Membrane / Q000201:enzymology*; D012623:Seawater / Q000382:microbiology*; D020592:Shewanella / Q000201:enzymology* / Q000302:isolation & purification; D012965:Sodium Chloride / Q000737:chemistry*; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D012965:Sodium Chloride; D015720:5'-Nucleotidase
keywords: 5′-Nucleotidase; Deep-sea; Growth environment; NaCl tolerance; Shewanella