The Wzz (Cld) protein in Escherichia coli: amino acid sequence variation determines O-antigen chain length specificity

The model system for Escherichia coli with O111 genes was used to determine the chain length specificity of the wzz genes from O1, O2, O7, and O157 strains. wzz genes from Escherichia coli strains O1, O2, O7, and O157 were cloned and transferred to P4657 which lacks O antigen genes. The results indicate that the O antigen chain length of the Escherichia coli O1, O2, O7, and O157 strains were altered by replacing specific amino acids in the wzz, suggesting that amino acid variation in wzz is responsible for the varying chain length of the O antigen.