Approx. 10% (wt/wt) total carbohydrate is present in GspB105 and approx. 9% (wt/wt) carbohydrate in GspB194. Carbohydrates contain N-acetylglucosamine and some amounts of glucose or mannose.
Truncated derivatives of GspB- GspB105, GspB274 and GspB194 are also glycosylated. These are freely secreted. Gtf and Orf4 (glycosyltransferases) mediate intracellular glycosylation of GspB. Gly and Nss also contribute to this process. These are encoded in the gspB-sec operon. Mutation of one of them abolishes GspB expression. Two serine-rich repeats (SRR1 and SRR2) are glycosylated. Glycosylation is essential for the GspB solubility.