Characterization of a PA14 domain-containing galactofuranose-specific β-d-galactofuranosidase from Streptomyces sp

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2017-07, Vol.81 (7), p.1314-1319
• Main Authors: Matsunaga, Emiko, Higuchi, Yujiro, Mori, Kazuki, Yairo, Nao, Toyota, Saki, Oka, Takuji, Tashiro, Kosuke, Takegawa, Kaoru
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cloning, Molecular; Escherichia coli - genetics; Escherichia coli - metabolism; galactomannan; Galactose - analogs & derivatives; Galactose - metabolism; Galactosides - chemistry; Galactosides - metabolism; Gene Expression; Glycoside Hydrolases - chemistry; Glycoside Hydrolases - genetics; Glycoside Hydrolases - metabolism; Kinetics; Mannans - chemistry; Mannans - metabolism; Phylogeny; Protein Domains; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Streptomyces - chemistry; Streptomyces - classification; Streptomyces - enzymology; Streptomyces species; Substrate Specificity; α-l-arabinofuranosidase; β-d-galactofuranosidase
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1080/09168451.2017.1300518

As a constituent of polysaccharides and glycoconjugates, β-d-galactofuranose (Galf) exists in several pathogenic microorganisms. Although we recently identified a β-d-galactofuranosidase (Galf-ase) gene, ORF1110, in the Streptomyces strain JHA19, very little is known about the Galf-ase gene. Here, we characterized a strain, named JHA26, in the culture supernatant of which exhibited Galf-ase activity for 4-nitrophenyl β-d-galactofuranoside (pNP-β-d-Galf) as a substrate. Draft genome sequencing of the JHA26 strain revealed a putative gene, termed ORF0643, that encodes Galf-ase containing a PA14 domain, which is thought to function in substrate recognition. The recombinant protein expressed in Escherichia coli showed the Galf-specific Galf-ase activity and also released galactose residue of the polysaccharide galactomannan prepared from Aspergillus fumigatus, suggesting that this enzyme is an exo-type Galf-ase. BLAST searches using the amino acid sequences of ORF0643 and ORF1110 Galf-ases revealed two types of Galf-ases in Actinobacteria, suggesting that Galf-specific Galf-ases may exhibit discrete substrate specificities. Galf-specific Galf-ases with discrete substrate recognition domains in Actinobacteria