RRC ID 34287
著者 Fujita K, Sakaguchi T, Sakamoto A, Shimokawa M, Kitahara K.
タイトル Bifidobacterium longum subsp. longum Exo-β-1,3-Galactanase, an enzyme for the degradation of type II arabinogalactan.
ジャーナル Appl Environ Microbiol
Abstract Type II arabinogalactan (AG-II) is a suitable carbohydrate source for Bifidobacterium longum subsp. longum, but the degradative enzymes have never been characterized. In this study, we characterized an exo-β-1,3-galactanase, BLLJ_1840, belonging to glycoside hydrolase family 43 from B. longum subsp. longum JCM1217. The recombinant BLLJ_1840 expressed in Escherichia coli hydrolyzed β-1,3-linked galactooligosaccharides but not β-1,4- and β-1,6-linked galactooligosaccharides. The enzyme also hydrolyzed larch wood arabinogalactan (LWAG), which comprises a β-1,3-linked galactan backbone with β-1,6-linked galactan side chains. The kcat/Km ratio of dearabinosylated LWAG was 24-fold higher than that of β-1,3-galactan. BLLJ_1840 is a novel type of exo-β-1,3-galactanase with a higher affinity for the β-1,6-substituted β-1,3-galactan than for nonsubstituted β-1,3-galactan. BLLJ_1840 has 27% to 28% identities with other characterized exo--1,3-galactanases from bacteria and fungi. The homologous genes are conserved in several strains of B. longum subsp. longum and B. longum subsp. infantis but not in other bifidobacteria. Transcriptional analysis revealed that BLLJ_1840 is intensively induced with BLLJ_1841, an endo-β-1,6-galactanase candidate, in the presence of LWAG. This is the first report of exo-β-1,3-galactanase in bifidobacteria, which is an enzyme used for the acquisition of AG-II in B. longum subsp. longum.
巻・号 80(15)
ページ 4577-84
公開日 2014-8-1
DOI 10.1128/AEM.00802-14
PII AEM.00802-14
PMID 24837371
PMC PMC4148793
MeSH Bacterial Proteins / chemistry Bacterial Proteins / genetics Bacterial Proteins / metabolism* Bifidobacterium / chemistry Bifidobacterium / classification Bifidobacterium / enzymology* Bifidobacterium / genetics Cloning, Molecular Enzyme Stability Galactans / metabolism* Glycoside Hydrolases / chemistry Glycoside Hydrolases / genetics Glycoside Hydrolases / metabolism* Kinetics Molecular Sequence Data Phylogeny Protein Structure, Tertiary Substrate Specificity
IF 4.016
引用数 15
WOS 分野 BIOTECHNOLOGY & APPLIED MICROBIOLOGY MICROBIOLOGY
リソース情報
一般微生物 JCM 1217