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Cite: NAR/gkaa742 2020



PUL General Information

Literature Information

PUL ID

PUL0008

PubMed

28103254, PLoS One. 2017 Jan 19;12(1):e0169989. doi: 10.1371/journal.pone.0169989. eCollection 2017.

Characterization method

enzyme activity assay

Genomic accession number

NC_004663.1

Nucelotide position range

2164759-2186087

Substrate

fructan

Loci

BT_RS08890-BT_RS08945

Species

Bacteroides thetaiotaomicron/818

Degradation or Biosynthesis

degradation

Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- BT_RS08890 WP_072067389.1 0 - 2763 (-) NC_004663.1:2164759-2167522 -
- BT_RS08895 WP_011107963.1 3086 - 4313 (-) NC_004663.1:2167845-2169072 -
- BT_RS08900 WP_005941495.1 4690 - 5686 (+) NC_004663.1:2169449-2170445 -
- BT_RS08905 WP_008767783.1 5871 - 6759 (-) NC_004663.1:2170630-2171518 -
- BT_RS08910 WP_008763289.1 6793 - 7963 (-) NC_004663.1:2171552-2172722 -
- BT_RS08915 WP_008767782.1 8242 - 10075 (-) NC_004663.1:2173001-2174834 -
- BT_RS08920 WP_032841481.1 10204 - 11773 (-) NC_004663.1:2174963-2176532 -
- BT_RS08925 WP_008763287.1 11791 - 13177 (-) NC_004663.1:2176550-2177936 -
- BT_RS08930 WP_008767780.1 13203 - 14916 (-) NC_004663.1:2177962-2179675 -
- BT_RS08935 WP_011107964.1 14943 - 18069 (-) NC_004663.1:2179702-2182828 -
- BT_RS08940 WP_008767778.1 18368 - 19241 (+) NC_004663.1:2183127-2184000 -
- BT_RS08945 WP_011107965.1 19445 - 21329 (-) NC_004663.1:2184204-2186088 -

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 2763 (-) TF: DBD-Pfam|HTH_AraC,DBD-SUPERFAMILY|0035607 No
- 3087 - 4313 (-) CDS No
- 4691 - 5686 (+) CDS No
- 5872 - 6759 (-) STP: STP|PfkB No
- 6794 - 7963 (-) TC: gnl|TC-DB|Q8A6W8|2.A.1.7.17 Yes
- 8243 - 10075 (-) CAZyme: GH32 Yes
- 10205 - 11773 (-) CAZyme: GH32 Yes
- 11792 - 13177 (-) other Yes
- 13204 - 14916 (-) TC: gnl|TC-DB|C6Y217|8.A.46.1.3 Yes
- 14944 - 18069 (-) TC: gnl|TC-DB|Q45780|1.B.14.6.1 Yes
- 18369 - 19241 (+) other Yes
- 19446 - 21329 (-) CAZyme: GH32 Yes

PUL ID

PUL0008

PubMed

28103254, PLoS One. 2017 Jan 19;12(1):e0169989. doi: 10.1371/journal.pone.0169989. eCollection 2017.

Title

A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass.

Author

Mardo K, Visnapuu T, Vija H, Aasamets A, Viigand K, Alamae T

Abstract

Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a beta-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3 of Pseudomonas syringae pv. tomato, its mutant Asp300Asn, levansucrases of Zymomonas mobilis, Erwinia herbicola, Halomonas smyrnensis as well as on levan isolated from timothy grass. For the first time a plant levan is shown as a perfect substrate for an endo-fructanase of a human gut bacterium. BT1760 degraded levans to FOS with degree of polymerization from 2 to 13. At optimal reaction conditions up to 1 g of FOS were produced per 1 mg of BT1760 protein. Low molecular weight (<60 kDa) levans, including timothy grass levan and levan synthesized from sucrose by the Lsc3Asp300Asn, were degraded most rapidly whilst levan produced by Lsc3 from raffinose least rapidly. BT1760 catalyzed finely at human body temperature (37 degrees C) and in moderately acidic environment (pH 5-6) that is typical for the gut lumen. According to differential scanning fluorimetry, the Tm of the endo-levanase was 51.5 degrees C. All tested levans were sufficiently stable in acidic conditions (pH 2.0) simulating the gastric environment. Therefore, levans of both bacterial and plant origin may serve as a prebiotic fiber for B. thetaiotaomicron and contribute to short-chain fatty acids synthesis by gut microbiota. In the genome of Bacteroides xylanisolvens of human origin a putative levan degradation locus was disclosed.