English: Schematic representation of the SARS-CoV-1 s2m RNA secondary structure, with tertiary structural interactions indicated as long-range contacts. s2m includes GNRA-like pentaloop structure (brown), A form RNA helices (blue and purple), the three-purine asymmetric bulge (orange), and the seven-nucleotide bubble (green). Long-range tertiary contacts are indicated by thin orange and brown lines. Formation of the junction of two perpendicular helices is facilitated by a base quartet (blue) composed of two G–C pairs.