Fig. 3.

Insertion of a glycosylation cluster results in S-layer glycosylation. RT023 contains a glycosylation cluster within the slp gene island. (a) Genomic organization of the slp gene island in 630 (Clade 1) and CD305 (Clade 3) showing loss of Cwp2 and acquisition of a gene cluster comprising putative glycosylation genes (adapted from Kirk et al. [18]). (b) Structure of SlpA in 630 and CD305 showing Cwp84 cleavage sites and truncated low-molecular weight (light grey) in CD305. (c) Coomassie staining of S-layer protein preparations from representative strains from each clade showing characteristic double banding for high-molecular weight and low-molecular weight S-layer protein (grey arrows). (d) Periodic acid–Schiff staining of glycans in S-layer preparations.