Fujimori Kiko, Fujii Sotaro, Lisdiana Lisa, Wakai Satoshi, Yagi Hisashi, Sambongi Yoshihiro
a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
b Department of Biology , Universitas Negeri Surabaya, Kampus Unesa Ketintang , Surabaya , Indonesia.
Biosci Biotechnol Biochem. 2019 Jun;83(6):1085-1093. doi: 10.1080/09168451.2019.1578641. Epub 2019 Feb 14.
Deep-sea Shewanella violacea 5'-nucleotidase (SVNTase) activity exhibited higher NaCl tolerance than that of a shallow-sea Shewanella amazonensis homologue (SANTase), the sequence identity between them being 70.4%. Here, SVNTase exhibited higher activity than SANTase with various inorganic salts, similar to the difference in their NaCl tolerance. In contrast, SVNTase activity decreased with various organic solvents, while SANTase activity was retained with the same concentrations of the solvents. Therefore, SVNTase is more robust than SANTase with inorganic salts, but more vulnerable with organic solvents. As to protein stability, SANTase was more stable against organic solvents and heat than SVNTase, which correlated with the differences in their enzymatic activities. We also found that SANTase retained higher activity for three weeks than SVNTase did in the presence of glycerol. These findings will facilitate further application of these enzymes as appropriate biological catalysts under various harsh conditions. Abbreviations: NTase: 5'-nucleotidase; SANTase: Shewanella amazonensis 5'-nucleotidase; SVNTase: Shewanella violacea 5'-nucleotidase; CD: circular dichroism.
深海紫色希瓦氏菌5'-核苷酸酶（SVNTase）的活性比浅海亚马逊希瓦氏菌的同源物（SANTase）表现出更高的耐NaCl能力，它们之间的序列同一性为70.4%。在此，SVNTase在各种无机盐存在下比SANTase表现出更高的活性，这与它们在耐NaCl能力上的差异相似。相反，SVNTase的活性在各种有机溶剂存在下降低，而SANTase在相同浓度的溶剂中仍保持活性。因此，SVNTase在无机盐存在下比SANTase更具耐受性，但在有机溶剂存在下更易受影响。至于蛋白质稳定性方面，SANTase比SVNTase对有机溶剂和热更稳定，这与其酶活性的差异相关。我们还发现，在甘油存在下，SANTase比SVNTase在三周内保持更高的活性。这些发现将有助于在各种苛刻条件下将这些酶作为合适的生物催化剂进一步应用。缩写：NTase：5'-核苷酸酶；SANTase：亚马逊希瓦氏菌5'-核苷酸酶；SVNTase：紫色希瓦氏菌5'-核苷酸酶；CD：圆二色性
