FIG. 2.

ifs is positioned between spn and slo on the bacterial chromosome and has multiple truncated variants. The genetic organization of the spn-slo operon is presented (A). A multiple alignment of ifs genes from several S. pyogenes strains is shown (B). The ifs sequence from the well-studied reference strain JRS4 is provided as an example of the full-length protein. Strain MGAS2109 has a truncation at amino acid site 24 secondary to the substitution of an adenine for a thymine at bp 71. Strain MGAS2111 has a truncation at amino acid site 24 secondary to the deletion of a thymine at bp 71. Strain SS116 has a truncation at amino acid site 19 secondary to the deletion of an adenine at bp 40. Strain 22RS72 has a truncation at amino acid site 24 secondary to the substitution of an adenine for a thymine at bp 71, similarly to MGAS2109, but also contains another truncation in the second open reading frame that begins at codon site 44. Polymorphic amino acid sites are shaded in black. An asterisk (*) indicates a stop codon. The designations of ifs as full length, truncated 1, truncated 2, or truncated 3 correspond to the ifs allele in Table S1 in the supplemental material.