PUL ID

PUL0055

PubMed

29795267, Sci Rep. 2018 May 23;8(1):8075. doi: 10.1038/s41598-018-26104-1.

Characterization method

sequence homology analysis

Genomic accession number

GL945092.1

Nucelotide position range

21043-32944

Substrate

alginate

Loci

HMPREF0127_01346-HMPREF0127_01352

Species

Bacteroides sp. 1_1_30/457387

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 2208 (-) CAZyme: PL17|PL17_2 Yes
- 2255 - 4519 (-) CAZyme: PL6|PL6_1 Yes
- 4523 - 6205 (-) other Yes
- 6226 - 7746 (-) TC: gnl|TC-DB|E4RVP8|8.A.46.1.5 Yes
- 7759 - 10941 (-) TC: gnl|TC-DB|Q45780|1.B.14.6.1 Yes
- 11044 - 11160 (-) CDS No
- 11183 - 11902 (+) TF: DBD-Pfam|GntR,DBD-SUPERFAMILY|0039384 No

PUL ID

PUL0055

PubMed

29795267, Sci Rep. 2018 May 23;8(1):8075. doi: 10.1038/s41598-018-26104-1.

Title

Ancient acquisition of "alginate utilization loci" by human gut microbiota.

Author

Mathieu S, Touvrey-Loiodice M, Poulet L, Drouillard S, Vincentelli R, Henrissat B, Skjak-Braek G, Helbert W

Abstract

In bacteria from the phylum Bacteroidetes, the genes coding for enzymes involved in polysaccharide degradation are often colocalized and coregulated in so-called "polysaccharide utilization loci" (PULs). PULs dedicated to the degradation of marine polysaccharides (e.g. laminaran, ulvan, alginate and porphyran) have been characterized in marine bacteria. Interestingly, the gut microbiome of Japanese individuals acquired, by lateral transfer from marine bacteria, the genes involved in the breakdown of porphyran, the cell wall polysaccharide of the red seaweed used in maki. Sequence similarity analyses predict that the human gut microbiome also encodes enzymes for the degradation of alginate, the main cell wall polysaccharide of brown algae. We undertook the functional characterization of diverse polysaccharide lyases from family PL17, frequently found in marine bacteria as well as those of human gut bacteria. We demonstrate here that this family is polyspecific. Our phylogenetic analysis of family PL17 reveals that all alginate lyases, which have all the same specificity and mode of action, cluster together in a very distinct subfamily. The alginate lyases found in human gut bacteria group together in a single clade which is rooted deeply in the PL17 tree. These enzymes were found in PULs containing PL6 enzymes, which also clustered together in the phylogenetic tree of PL6. Together, biochemical and bioinformatics analyses suggest that acquisition of this system appears ancient and, because only traces of two successful transfers were detected upon inspection of PL6 and PL17 families, the pace of acquisition of marine polysaccharide degradation system is probably very slow.