TY - JOUR
T1 - Identification and characterization of a novel galactofuranose-specific β-D-galactofuranosidase from Streptomyces species
AU - Matsunaga, Emiko
AU - Higuchi, Yujiro
AU - Mori, Kazuki
AU - Yairo, Nao
AU - Oka, Takuji
AU - Shinozuka, Saki
AU - Tashiro, Kosuke
AU - Izumi, Minoru
AU - Kuhara, Satoru
AU - Takegawa, Kaoru
N1 - Funding Information:
We thank Dr. Mitsuaki Tabuchi of Kagawa University, for the kind gift of bacterial strains, and Dr. Takane Katayama of Kyoto University, for the gift of ΔlacZ E. coli strain. We also appreciate Dr. Masatoshi Goto of Kyushu University, for continuous discussions. This study was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (K.T.) and (Y.H.).
Publisher Copyright:
© 2015 Matsunaga et al.
PY - 2015/9/4
Y1 - 2015/9/4
N2 - β-D-galactofuranose (Galf) is a component of polysaccharides and glycoconjugates and its transferase has been well analyzed. However, no β-D-galactofuranosidase (Galf-ase) gene has been identified in any organism. To search for a Galf-ase gene we screened soil samples and discovered a strain, identified as a Streptomyces species by the 16S ribosomal RNA gene analysis, that exhibits Galf-ase activity for 4-nitrophenyl β-D-galactofuranoside (pNP-β-D-Galf) in culture supernatants. By draft genome sequencing of the strain, named JHA19, we found four candidate genes encoding Galf-ases. Using recombinant proteins expressed in Escherichia coli, we found that three out of four candidates displayed the activity of not only Galf-ase but also α-L-arabinofuranosidase (Araf-ase), whereas the other one showed only the Galf-ase activity. This novel Galf-specific hydrolase is encoded by ORF1110 and has an optimum pH of 5.5 and a Km of 4.4 mM for the substrate pNP-β-D-Galf. In addition, this enzyme was able to release galactose residue from galactomannan prepared from the filamentous fungus Aspergillus fumigatus, suggesting that natural polysaccharides could be also substrates. By the BLAST search using the amino acid sequence of ORF1110 Galf-ase, we found that there are homolog genes in both prokaryotes and eukaryotes, indicating that Galf-specific Galf-ases widely exist in microorganisms.
AB - β-D-galactofuranose (Galf) is a component of polysaccharides and glycoconjugates and its transferase has been well analyzed. However, no β-D-galactofuranosidase (Galf-ase) gene has been identified in any organism. To search for a Galf-ase gene we screened soil samples and discovered a strain, identified as a Streptomyces species by the 16S ribosomal RNA gene analysis, that exhibits Galf-ase activity for 4-nitrophenyl β-D-galactofuranoside (pNP-β-D-Galf) in culture supernatants. By draft genome sequencing of the strain, named JHA19, we found four candidate genes encoding Galf-ases. Using recombinant proteins expressed in Escherichia coli, we found that three out of four candidates displayed the activity of not only Galf-ase but also α-L-arabinofuranosidase (Araf-ase), whereas the other one showed only the Galf-ase activity. This novel Galf-specific hydrolase is encoded by ORF1110 and has an optimum pH of 5.5 and a Km of 4.4 mM for the substrate pNP-β-D-Galf. In addition, this enzyme was able to release galactose residue from galactomannan prepared from the filamentous fungus Aspergillus fumigatus, suggesting that natural polysaccharides could be also substrates. By the BLAST search using the amino acid sequence of ORF1110 Galf-ase, we found that there are homolog genes in both prokaryotes and eukaryotes, indicating that Galf-specific Galf-ases widely exist in microorganisms.
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U2 - 10.1371/journal.pone.0137230
DO - 10.1371/journal.pone.0137230
M3 - Article
C2 - 26340350
AN - SCOPUS:84944327065
VL - 10
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 9
M1 - e0137230
ER -