The CsaB protein (cell surface anchoring B) of Bacillus anthracis adds a pyruvoyl group to peptidoglycan-associated polysaccharide. This addition is required for proteins with an S-layer homology domain (pfam00395) to bind. Within the larger group of proteins described by pfam04230, this model represents a distinct clade that nearly exactly follows the phylogenetic distribution of the S-layer homology domain (pfam00395). [Cell envelope, Surface structures, Protein fate, Protein and peptide secretion and trafficking]
Jiyao W et al.(2023). "The conserved domain database in 2023.",