Because CGCFinder predicted no CGC for this PUL, the gene cluster depicted below contains dbCAN2 and CGC signature predictions for all genes in the PUL, instead of a predicted CGC.


PUL ID

PUL0194

PubMed

28056108, PLoS Pathog. 2017 Jan 5;13(1):e1006090. doi: 10.1371/journal.ppat.1006090. eCollection 2017 Jan.

Characterization method

enzyme activity assay, gene deletion mutant and growth assay

Genomic accession number

AE005672.3

Nucelotide position range

2050572-2061389

Substrate

N-glycan

Loci

SP_2141-SP_2146

Species

Streptococcus pneumoniae/1313

Degradation or Biosynthesis

degradation

Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- SP_2141 AAK76198.1 0 - 1881 (-) AE005672.3:2050572-2052453 -
- SP_2142 AAK76199.1 1874 - 2744 (-) AE005672.3:2052446-2053316 -
- SP_2143 AAK76200.1 2826 - 5487 (-) AE005672.3:2053398-2056059 -
- SP_2144 AAK76201.1 5562 - 6843 (-) AE005672.3:2056134-2057415 -
- SP_2145 AAK76202.1 7014 - 9099 (+) AE005672.3:2057586-2059671 -
- SP_2146 AAK76203.1 9138 - 10818 (-) AE005672.3:2059710-2061390 -

Cluster number

0

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1881 (-) CAZyme: GH20 No
- 1875 - 2744 (-) CDS No
- 2827 - 5487 (-) CAZyme: GH38 No
- 5563 - 6843 (-) CAZyme: GH125 No
- 7015 - 9099 (+) CAZyme: GH92 No
- 9139 - 10818 (-) CAZyme: GH29 No

PUL ID

PUL0194

PubMed

28056108, PLoS Pathog. 2017 Jan 5;13(1):e1006090. doi: 10.1371/journal.ppat.1006090. eCollection 2017 Jan.

Title

Molecular Characterization of N-glycan Degradation and Transport in Streptococcus pneumoniae and Its Contribution to Virulence.

Author

Robb M, Hobbs JK, Woodiga SA, Shapiro-Ward S, Suits MD, McGregor N, Brumer H, Yesilkaya H, King SJ, Boraston AB

Abstract

The carbohydrate-rich coating of human tissues and cells provide a first point of contact for colonizing and invading bacteria. Commensurate with N-glycosylation being an abundant form of protein glycosylation that has critical functional roles in the host, some host-adapted bacteria possess the machinery to process N-linked glycans. The human pathogen Streptococcus pneumoniae depolymerizes complex N-glycans with enzymes that sequentially trim a complex N-glycan down to the Man3GlcNAc2 core prior to the release of the glycan from the protein by endo-beta-N-acetylglucosaminidase (EndoD), which cleaves between the two GlcNAc residues. Here we examine the capacity of S. pneumoniae to process high-mannose N-glycans and transport the products. Through biochemical and structural analyses we demonstrate that S. pneumoniae also possesses an alpha-(1,2)-mannosidase (SpGH92). This enzyme has the ability to trim the terminal alpha-(1,2)-linked mannose residues of high-mannose N-glycans to generate Man5GlcNAc2. Through this activity SpGH92 is able to produce a substrate for EndoD, which is not active on high-mannose glycans with alpha-(1,2)-linked mannose residues. Binding studies and X-ray crystallography show that NgtS, the solute binding protein of an ABC transporter (ABCNG), is able to bind Man5GlcNAc, a product of EndoD activity, with high affinity. Finally, we evaluated the contribution of EndoD and ABCNG to growth of S. pneumoniae on a model N-glycosylated glycoprotein, and the contribution of these enzymes and SpGH92 to virulence in a mouse model. We found that both EndoD and ABCNG contribute to growth of S. pneumoniae, but that only SpGH92 and EndoD contribute to virulence. Therefore, N-glycan processing, but not transport of the released glycan, is required for full virulence in S. pneumoniae. To conclude, we synthesize our findings into a model of N-glycan processing by S. pneumoniae in which both complex and high-mannose N-glycans are targeted, and in which the two arms of this degradation pathway converge at ABCNG.