Figure. Amplification and characterization of a newly discovered open reading frame (ORF) of Streptococcus anginosus. A) Gel electrophoresis after emm-PCR on S. anginosus isolate SV52 (SV52) and S. pyogenes strain A60 (A60). The latter isolate was used as a control that possesses an emm3 gene. The S. anginosus strain generated a low concentration 1.1-kb amplicon, as compared with the 1.4-kb product of the S. pyogenes strain. Inverse PCR based on the 1.1-kb sequence of SV52 showed an ORF of 3,363 bp. Its sequence is predicted to code for the membrane protein that is schematically depicted in panel B. It comprises an N terminal signal peptide (S) followed by a large extracellular region of 60 kDa (ECR1), 7 transmembrane helixes (1–7), and another large extracellular region of 23 kDa situated between the fourth and the fifth transmembrane helix (ECR3). Positions of the 2 alternative marker of Streptococcus anginosus and S. constellatus PCR products (I and II) relative to the full-length sequence and their length are indicated in basepairs.