28837839, Carbohydr Res. 2017 Oct 10;450:19-29. doi: 10.1016/j.carres.2017.08.006. Epub 2017 Aug 18.

Characterization method

sequence homology analysis,sugar utilization assay,NMR,gas chromatography and mass spectrometry

Genomic accession number


Nucelotide position range







Streptococcus pneumoniae/1313

Degradation or Biosynthesis


Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

wzg 1204 - 2649 (+) CDS No
wzh 2651 - 3382 (+) CDS No
wzd 3391 - 4083 (+) TC: gnl|TC-DB|Q93E03|8.A.3.2.3 Yes
wze 4093 - 4776 (+) TC: gnl|TC-DB|Q93NW3|8.A.3.2.2 Yes
wchA 4792 - 6159 (+) TC: gnl|TC-DB|H8E4X1|9.B.18.1.2 Yes
wchF 6190 - 7368 (+) CAZyme: GT4 Yes
wzy 7578 - 8984 (+) other Yes
wchV 8984 - 9955 (+) TC: gnl|TC-DB|P75905|4.D.1.1.3 Yes
wchW 9962 - 11194 (+) CDS No
wzx 11196 - 12581 (+) CDS No
wchX 12589 - 13737 (+) CDS No
gtp1 13773 - 14801 (+) CDS No
gtp2 14817 - 15521 (+) CDS No
gtp3 15536 - 16369 (+) CDS No
rmlA 16529 - 17398 (+) CDS No
rmlC 17399 - 17992 (+) CDS No
rmlB 18005 - 19054 (+) CDS No
rmlD 19120 - 19971 (+) CDS No




28837839, Carbohydr Res. 2017 Oct 10;450:19-29. doi: 10.1016/j.carres.2017.08.006. Epub 2017 Aug 18.


Genetic and structural elucidation of capsular polysaccharides from Streptococcus pneumoniae serotype 23A and 23B, and comparison to serotype 23F.


Ravenscroft N, Omar A, Hlozek J, Edmonds-Smith C, Follador R, Serventi F, Lipowsky G, Kuttel MM, Cescutti P, Faridmoayer A


Streptococcus pneumoniae is a globally important encapsulated human pathogen with approximately 100 different serotypes recognized. Serogroup 23 consists of serotype 23F, present in licensed vaccines, and emerging serotypes 23A and 23B. Here, we report the previously unknown structures of the pneumococcal capsular polysaccharides serotype 23A and 23B determined using genetic analysis, NMR spectroscopy, composition and linkage analysis and Smith degradation (of polysaccharide 23A). The structure of the serotype 23A capsular polysaccharide is: -->4)-beta-D-Glcp-(1-->3)-[[alpha-L-Rhap-(1-->2)]-[Gro-(2-->P-->3)]-beta-D-Galp-(1-->4)]-beta-L-Rhap-(1-->. This structure differs from polysaccharide 23F as it features a disaccharide backbone and the di-substituted beta-Gal is linked to beta-Rha as a side chain. This is due to the different polymerization position catalysed by the unusually divergent repeat unit polymerase Wzy in the 23A cps biosynthesis locus. Steric crowding in 23A, confirmed by molecular models, causes the NMR signal for H-1 of the di-substituted 2,3-beta-Gal to resonate in the alpha-anomeric region. The structure of the serotype 23B capsular polysaccharide is the same as 23F, but without the terminal alpha-Rha: -->4)-beta-D-Glcp-(1-->4)-[Gro-(2-->P-->3)]-beta-D-Galp-(1-->4)-beta-L-Rhap-(1-->. The immunodominant terminal alpha-Rha of 23F is more sterically crowded in 23A and absent in 23B. This may explain the reported typing cross reactions for serotype 23F: slight with 23A and none with 23B.